♪♪ ♪♪ ♪♪ ♪♪ -Today on "America's Test Kitchen," Becky makes Julia spinach lasagna.

Jack talks all about preserved fruits.

Dan reveals the science of what happens in a pressure cooker, and Lan makes Bridget pasta e piselli.

It's all coming up right here on "America's Test Kitchen."

"America's Test Kitchen" is brought to you by the following.

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♪♪ -Whenever I think about spinach lasagna, I think about a version we developed here in the test kitchen back in 2004 as the absolute best, and it was developed by our very own Becky, and it's never been on the show before.

-So excited to finally do it on TV.

-Me too.

It's a terrific recipe.

-Thank you.

Yeah, I can't believe it's 20 years old, but it has a couple of neat tricks and I think it's stood the test of time.

-It has.

-It really locks in that green, fresh flavor of the spinach, and it's so creamy and cheesy.

-Yeah.

-This is really fun.

This is just 1 1/4 pound of spinach.

We're going to put it in 4 quarts of boiling water.

And I'm gonna add a tablespoon of salt.

-Okay.

-And we're just gonna put it in here for five seconds, really fast, just long enough to wilt it down.

But it's going to keep that nice bright color.

So all right.

In it goes.

All right, I'm gonna take it out.

-All right.

-So a spider is the best way to get this out.

And I'm going to put this into some ice water.

That's gonna stop the cooking, lock in that beautiful color.

-Yeah.

-Now I have a kitchen towel.

I'm going to spread this out.

Try not to get too many ice cubes in there.

See how much that wilted down already?

-Mm-hmm.

-So we don't want any water to be in our lasagna.

We don't want a watery lasagna.

So putting it on a dish towel here.

Now I'm just going to swaddle it up.

And I like this little job.

-Yeah.

-I don't know about you.

-It's very satisfying.

-It's very satisfying.

And it's pretty cool to see.

We started with so much spinach and watch what it's gonna turn into.

And all that spinach has been compressed down now into a little ball.

Isn't that crazy?

-I know.

-Okay, so let's unwrap our little ball of spinach here.

Beautiful color.

And now I'm just gonna chop it up.

And I like to keep it in a tight ball when I do this.

And yeah, this is fun too.

-It is fun.

-You just kind of run your knife right through it, and you chop that little ball up into pieces, and I turn it crosswise.

Doesn't have to be perfect.

And I just run through it one more time.

-Mm-hmm.

-All right.

So that's definitely worth it.

Better than using frozen.

This is going to be so nice in our lasagna.

All right.

Now we're going to make a Béchamel sauce, which is a milk sauce that's thickened with a roux.

And we're starting with 5 tablespoons of unsalted butter melting over medium heat here.

And I have 6 shallots.

That's a lot.

-That's a lot.

-Minced up.

But I wanted to give the sauce a really nice allium flavor.

Lots of savory notes in the sauce.

So that's why I'm using so many.

I'm also adding 4 garlic cloves.

Get those in.

Okay, so we're gonna let this cook for about 4 minutes, just until those shallots start to soften up a little bit.

And we'll start to smell the garlic a little bit, too.

All right.

It's been about 4 minutes.

You can see the shallots are getting soft there.

So I'm going to add 1/4 cup of flour.

We're making a roux.

This is gonna thicken the sauce.

So we just want to cook this for about a minute.

We just want to eliminate the raw taste of the flour.

All right.

It's been a minute.

Our roux is ready to go.

Now I'm gonna add 3 1/2 cups of milk.

I'm going to switch to a whisk for this.

This is whole milk.

Yeah, I like whole milk for this.

I want this to be, you know, really creamy and rich.

So yeah, I wouldn't use low fat or skim for this.

And I'm making this sauce purposely thin.

We're going to be using no-boil noodles.

And those give off a fair amount of starch in the oven.

So we want a thin sauce because it's going to get thickened by all that starch.

All right, I'm going to increase the heat to medium-high here.

I want to bring this up to a boil.

All right.

Our sauce is boiling there.

So I'm going to add a couple more seasonings.

2 bay leaves.

3/4 teaspoon of nutmeg.

There we go.

Love the smell of nutmeg.

-Mm-hmm.

-And then 1/2 teaspoon of salt and 1/4 teaspoon of pepper.

Now I'm just going to turn the heat down to low and let this simmer for about 10 minutes, whisking it occasionally.

It's gonna thicken up a little bit, turn nice and glossy, and we'll be ready to continue.

-All right.

-Okay, it's been 10 minutes, and you can see our sauce has really thickened up quite a bit.

It should be about the consistency of heavy cream.

-Okay.

-That looks just right.

So I'm gonna take those bay leaves out.

All right.

So now I have 1/2 cup of Parmesan cheese.

I told you things were going to get cheesy in here.

-Mm-hmm.

-All right.

So that'll just give a nice nuttiness to the sauce.

Whisk that in until it melts.

Okay, so I'll transfer this to a bowl so it can cool down a little bit.

I'm just going to put some plastic wrap on top of that.

And I'm going to press it right onto the surface.

I don't want a skin to form.

-Mm-hmm.

The old pudding trick.

-That's right.

That'll keep that sauce nice and fresh.

And now we're going to move on to our cheese filling.

So this is a cup of whole milk cottage cheese, and it is a little bit of an odd ingredient, but I found that the cottage cheese has this really nice creaminess, and it has a little bit of a tang to it.

So there's a cup of that whole milk cottage cheese.

We're gonna blend it up in the food processor.

You can also use a blender for this step if you like.

I'm gonna put in an egg, and that'll just help it set up a little bit when it bakes.

And 1/4 teaspoon of salt.

So we're just going to whizz that up for about 30 seconds until it gets nice and creamy.

All right.

That was 30 seconds.

Oh, perfect.

So creamy.

Now just like with the milk, I wouldn't use skim cottage cheese here either.

Go for -- If you're making this, do it right.

Go for the full fat.

-It's true.

-All right.

So our sauce is ready.

Our cheese filling is ready.

So now we'll go over and we'll get our noodles ready.

-Okay.

-So if you wouldn't mind, I have some boiling water here.

We need about 2 inches into our baking dish.

-Okay.

Looks good, huh?

-That's perfect.

-All right.

-So we're gonna be using Barilla no-boil noodles.

-Mm-hmm.

-They really cook up.

They taste like fresh pasta.

They're really nice and thin.

And normally you just go ahead and assemble them in your lasagna.

But I'm gonna give them a little bit of a head start, and I'm gonna soak them for 5 minutes in the boiling water.

-Mm-hmm.

-And the reason I'm doing that is I don't want the lasagna to be in the oven for too long, because I want to maintain that nice fresh spinach color and flavor.

So the lasagna will just have to be in the oven for 20 minutes.

-Oh, nice.

-Yeah.

-And I like how you pointed out the brand of no-boil noodles because they're not all the same.

Some of them are much thicker and require more liquid in the sauce than this recipe has.

So the brand matters here.

-Yeah.

You really want to look for the Barilla.

So I put 12 noodles into the water and I'm letting them soak for 5 minutes.

-Okay, so as the name suggests, no-boil noodles don't need to be boiled before you use them, unlike traditional noodles.

Here's why.

Traditional noodles are made from a flour and water dough which is then dried.

Inside the noodles, there are two key components, starch granules and protein.

When they're boiled, heat forces the starch granules to absorb water, which causes them to swell up and gel, resulting in a tender yet toothsome noodle texture.

No-boil noodles are made the same way, using the same ingredients, flour and water, but they are parcooked at the factory.

After they go through this cooking process, the noodles are rapidly dried so that the starch is pregelatinized and set.

These noodles only need to be reheated briefly in order to rehydrate that gel, as opposed to the extensive boiling that traditional noodles require in order to cook the starch.

And that makes no-boil noodles a real time saver when making lasagna.

All right, now comes the fun part where we get to assemble the lasagna.

So we took the noodles out of the boiling water, and I have them on a couple layers of towels here.

You can see they're nice and pliable, so they're partially rehydrated, which is exactly what we want.

All right, let's put this together.

Let's start with 1/2 cup of our sauce.

And I have a 13x9" baking dish here.

And it's been greased.

-Mm-hmm.

-So this is how lasagna usually starts.

You usually put a layer of sauce on the bottom of the pan just so things have a little bit of moisture to soak up and so it doesn't stick.

-Mm-hmm.

-Spread that out a little bit.

All right, now before we continue, I have all our spinach that we cooked earlier.

I'm gonna add that into the sauce.

All right, I'm giving this a really good stir.

That spinach tends to clump up because I gave it such a good squeeze in that towel.

So I'm just stirring it pretty vigorously here.

I want to break up the spinach so it's separated.

Let's build our lasagna.

-Okay.

-So I'm gonna start with three noodles going on the bottom here.

And now a cup of the spinach Béchamel filling.

So we'll just divvy that up.

It doesn't have to be perfect.

It all kind of melts out in the oven and turns into a really nice casserole.

So spread that out a little bit.

Okay, that looks good.

-Mm-hmm.

-Now I have a cup of Parmesan cheese.

-Mm-hmm.

-Told you it was gonna be cheesy.

-It's so good.

-Yeah.

All right.

Now we'll go in with three more noodles.

It really feels like fresh pasta.

-Mm-hmm.

It's amazing what that little soaking time does.

-Yep.

All right.

Now another cup of our mixture.

Trying not to neglect the corners here.

Sometimes you can build a lasagna and it's really thick in the middle.

-It's like a little volcano in the middle.

Yeah.

So spread all the way to the corners.

All right.

And now we're using some Italian Fontina.

The Fontina has a nice, nutty, kind of buttery flavor.

It's really good.

-And it's such a good melter.

-Yes, it is.

All right.

So that's a cup of Fontina going on.

So you want to make sure you get Italian Fontina.

You don't want to use Danish or American.

That's a little bit more mild.

-Mm-hmm.

-Now we'll go for three more noodles.

All right.

Another cup of our spinach Béchamel mixture.

All right, here comes our cottage cheese.

Our secret ingredient.

-Mm-hmm.

-So just kind of drizzle that over.

Ooh.

You can see how creamy that is.

-Yep.

-Ooh.

Love it.

Okay.

Spread that out a little bit.

All right.

Three more noodles.

Our last -- last layer here.

-Mm-hmm.

-Now the rest of our filling.

Let's make sure we get every -- every little bit.

-Oh, yeah.

-All right.

This is looking pretty good here.

-Mm-hmm.

So now we're gonna cap it off with one more cup of Fontina.

So we got a really nice cheesy layer on top.

All right.

That looks really good.

-Mm-hmm.

-So I'm gonna cover this with some aluminum foil that I've sprayed so it doesn't stick.

So we're just gonna bake this for 20 minutes in a 425-degree oven.

A really short time because those noodles are already soft.

We just want to warm this up, get it nice and hot.

And that way the spinach will stay nice and fresh.

I'm gonna rotate this halfway through baking.

All right.

It's been 20 minutes.

Let's take a peek.

-Mmm.

-Ohhh.

Looking good.

-It smells amazing.

-It does, it does.

I just want to pop this under the broiler for 4 to 6 minutes.

I adjusted the oven rack so it's 6 inches below the elements, because I want it to get nice and spotty brown on top.

-Yep.

Mmm.

Goodness, Becky.

-Ooh.

That looks tasty.

-It looks perfect.

-Ooh.

-Nice and bubbling.

We got nice spotty browning on there.

-Mm-hmm.

And it's ripping hot.

-It's very hot.

We're gonna wait 15 minutes so it can kind of cool down just enough.

-Mm-hmm.

-And then it'll be time to eat.

-Okay.

-All right.

You've been waiting patiently for 15 minutes.

-Thank you for noticing.

Ohh.

-Using a paring knife.

That's the easiest way to cut it here.

-Mm-hmm.

-And it's really important to wait.

It not only cools off, but it kind of sets up a little bit in those 15 minutes.

It's worth the wait.

-Mm-hmm.

And we got the corner pieces.

-I know.

-Oh, yum.

-All right, you see how that set up really nicely?

-Mm-hmm.

Mmm.

The spinach comes right through.

-Mm-hmm.

-Has a bright spinach flavor.

-Mm-hmm.

-But then the Béchamel with the shallots and the nutmeg is right behind it.

It's such a lovely flavor all together with the Fontina.

You get that Parmesan.

-Mm-hmm.

-The nuttiness from the Fontina.

-Yep.

-And the noodles are perfectly tender.

They taste like fresh pasta.

-They really do.

And that cottage cheese.

Would you ever guess it was cottage cheese?

-Mnh-mnh.

-You just notice it's nice and creamy, just a little bit tangy.

And the spinach is super fresh.

You can still see it has a beautiful green color.

-Yep.

-It's not olive.

It's not drab.

-Ohh.

This is the best version I've ever had.

Becky, thank you for making it.

-Oh, it was fun.

-If you want to make the ultimate spinach lasagna, start by blanching and shocking sturdy spinach, then wring it dry.

Swap in cottage cheese and Italian Fontina for the ricotta and mozzarella, and give the no-boil noodles a quick head start by soaking them in hot water before assembling the lasagna.

From "America's Test Kitchen," Becky's own spinach lasagna.

This really is the best spinach lasagna out there.

-Aww.

♪♪ -What do you get when you combine fruit, sugar, and pectin?

Magic.

Preserves feel like kitchen alchemy.

That liquid fruit, because of the pectin, eventually sets up so you can spread it on your toast.

Now, pectin is an insoluble fiber.

It's naturally derived from apples, quinces, pears, citrus fruits, and it's the thing that makes everything on this table wonderful.

Now, it can be a little confusing when you go shopping because the category is called preserves, but so is the first thing here on the table.

So when you see something labeled a preserve, typically it's got large pieces of fruit.

And I will say manufacturers can do whatever they want, and so these are basically best practices.

And you see in these strawberry preserves that there are large, either whole or significant-sized chunks of fruit in the thick syrup.

Because there's so much fruit, usually equal amounts fruit and sugar, preserves tend to be less sweet than some of the other things on the table.

Raspberry jam here, and jam has either got crushed or very small pieces of fruit.

It's sweeter than preserves.

You see the seeds are left in here, which is okay, but you wouldn't see large pieces of strawberries, for example, in a jam.

Jelly -- Now, jelly is completely smooth.

It kind of wiggles here on the spoon a little bit.

This is made from fruit juice.

The solids are strained off.

It's got a lot of sugar and a lot of pectin to get it to set up.

This is grape jelly.

Next up, marmalade.

Typically made with sour oranges.

And this has got the peel and the zest.

So it's got the whole fruit is being used here.

And you can see the slices of orange peel.

Next up, conserves.

Now, these last two things on the table are really sweet and savory and actually kind of better with savory foods.

Now, a conserve is thick and chunky like a marmalade, but has dried fruit and/or nuts.

This one has dates, and I think there's some dried cranberries hiding inside this carrot conserve, which would be lovely with a roast pork loin.

Last but not least, we have chutney.

This is a mango chutney, and the two things that distinguish a chutney from everything else on the table are vinegar, so it's got a nice acidic bite, and then spices, mustard seeds that you can see here.

There's also I believe some chili in this one.

So again, this is a great partner for a pork chop or something savory.

So there you have it.

Preserves -- magic in a jar.

♪♪ -Here is stock that I made by boiling chicken parts in water in a pot on the stove.

And here is stock that I made using a pressure cooker.

As you can see, the stove-top stock cooked at 212 degrees is cloudy.

That's because the violent movement of the boiling water emulsified fats and protein into the water.

But the pressure cooker stock, which cooked much hotter, at about 240 degrees, is basically clear.

How is this possible?

Well, to find out, we pressure cooked a camera.

Take a look.

You can see that the water first boils at 212 degrees, at which point the pressure valve closes and the temp starts to rise to about 240 degrees.

Now as the pressure rises, the boiling slows to a simmer.

That's because the vapor pressure of the liquid is counterbalanced by the pressure of the vapor above it.

This is one reason pressure cookers and multi cookers are so valuable.

They cook at much higher temperatures, but without the aggressive agitation of boiling water.

They turn out crystal-clear stocks and tender but intact beans, grains, and meats.

This is also why if you're going for stock clarity like this, you should release the pressure naturally instead of doing a quick release, because that would cause the stock to boil and become cloudy.

♪♪ -Some of the most iconic and comforting dishes to come out of Italy, well, they were born out of an economic mindset, and I really appreciate that.

Pasta is combined with really inexpensive items like legumes.

You've got beans, pasta e fagioli, chickpeas, pasta e ceci.

And in the same vein, today we're gonna take green peas and turn them into pasta e piselli.

Lan's here.

She's gonna show us how it's done.

-Bridget, this "stoup," if you will, is great.

It's really quick.

It's really easy.

It's filling though, but a little bit lighter than the two pasta dishes you mentioned.

-Okay.

-We're gonna start with an onion.

I am just going to cut this in half, and I want to chop this finely.

I like to make the horizontal cuts first.

Have a little bit more control over the pieces as I'm cutting.

And then I'll make the vertical cuts.

And then it's just a matter of running the knife through the onion to finely chop.

One more bit of knife work.

I've got 2 ounces of pancetta here, and I'm going to chop this finely as well.

Pancetta is done.

We can start cooking.

-Okay, great.

-I've got a large saucepan here with 2 tablespoons of extra virgin olive oil.

It's been heating over medium heat, and it's just come to a shimmer, so we can add our ingredients.

And everything is just going to go right in, that onion, the pancetta.

Last up, I've got 1/2 teaspoon of table salt and 1/2 teaspoon of pepper.

Give this a quick stir.

-Okay.

-And I'm gonna cook this until the onions are translucent.

It's gonna take maybe 7, 10 minutes.

-Okay.

-It's been 7 minutes.

You can see the onions have really collapsed and they're quite translucent.

I'm going to get our liquids in.

I've got 2 1/2 cups of water.

And 2 1/2 cups of chicken broth.

And I'll just turn this up and let it come to a boil.

We're up to a boil.

It's time to add the pasta.

-Okay.

-I'm using ditalini because it's fairly traditional, but really, any small extruded pasta is gonna work here, whether we're talking about elbow, ditali, which are a tiny bit larger and thicker.

You want something small that cooks quickly because this dish isn't supposed to be something that takes hours.

-Plus it's a soup.

You want small, so it fits on a spoon.

-Exactly.

So now that the water has come up to a boil, I'm just gonna add 7 1/2 ounces of ditalini here.

That's 1 1/2 cups.

And it's just gonna go right in.

Now I want to stir this as I wait for that liquid to come back up to a boil.

Otherwise the pasta might glue itself to the bottom of the pot.

What is really great about this method is the starches from that pasta, it gives the broth a little bit of body and a little bit of silkiness.

It's really nice texture.

Now that we're up to a boil, I'm going to reduce this to maintain a simmer.

Pop a lid on there so we don't lose too much water to evaporation.

Cook that until the ditalini is al dente.

That's gonna be 8 to 10 minutes.

-Okay.

-It's been 8 minutes.

Let's have a peek.

-Ohh.

-Yeah.

Yeah, this is definitely done, but I'm gonna taste some anyway.

-All right.

-Perfect.

I have frozen peas here.

I really like frozen peas for this.

They're just gonna go right in.

So that was 1 1/2 cups of frozen peas.

And I'll give this a quick stir.

And I'm just gonna shut this off.

There's enough heat in there to cook those peas through without overcooking them.

So let's move this off heat.

-Okay.

-And we'll get to our garnishes.

-Nice.

-I have some parsley here, and I need 1/3 cup minced.

And run my knife through it.

When I mince herbs, I really want to make sure that I'm slicing through.

There's something about damaged herbs that makes them taste old.

So besides the parsley, I'm gonna add 2 tablespoons of mint.

I've got my leaves in a stack this time.

I can't quite mash the mint leaves together because they're so much more delicate.

And I'm just going to go through and come across in one direction.

All right.

So this is gonna go right into that pot.

-Mmm.

Lovely.

-And one last item.

I've got a 1/4 cup of Pecorino Romano in here.

I think it's really important to use Pecorino Romano because it's a sheep's milk cheese that offers a little bit more tang and that same savoriness as Parmesan.

And it just works really well.

It brightens up this dish nicely.

That's it.

We're done.

-That's -- Not only economy in terms of ingredients, but it's economical in terms of time.

This came together really quickly.

-It's a quick one.

One quick taste.

-Okay.

-And, um, I think the salt's good here, but I'm gonna add a little bit of pepper.

I can't wait for you to taste this.

-You aren't kidding when you talk about stoups.

-Right?

It's filling, but light, which is a hard thing to accomplish.

-My goodness.

-Pecorino?

-Yes, please.

I'll take a little bit.

-Just one tiny drizzle of olive oil.

-Gorgeous.

-For a little bit of green grassiness to complement those herbs.

-Mmm.

I can't wait to tuck in here.

That's wonderful.

-How great is that?

-The mint, the parsley at the end.

-Yeah.

-Beautiful.

Wakes it up.

And you're right, that little bit tanginess from the -- the Pecorino Romano is gorgeous.

It tastes like spring.

This is so easy, elegant, came together so quickly.

Economically.

-Mm-hmm.

-It's beautiful.

Thanks so much, Lan.

-You're welcome.

-Well, if you'd like to make this quick and easy and elegant pasta dish, it starts with sautéing pancetta to add deep, meaty flavor.

Stir the pasta frequently to prevent sticking.

And finish the dish with peas, mint, and tangy Pecorino.

So from "America's Test Kitchen," the economical but so elegant pasta e piselli.

You can get this recipe and all the recipes from this season, along with product reviews and select episodes.

And those are all on our website, AmericasTestKitchen.com/TV.

Gorgeous.

-Yeah, I'm gonna go find a place to take a nap after this.

-Yeah.

This is -- This is nap food.

-Visit our website to sign up for our free e-mail newsletter, with more revolutionary recipes and the stories behind 25 years of test-kitchen discoveries.

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