A Hamburger Today

The Food Lab Turbo: Creamy Brussels Sprouts Lasagna

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[Photographs: J. Kenji Lopez-Alt]

There seems to be a misconception that vegetarians and vegetarian food are, by definition, healthy and light. At least, for the sake of this article, let's pretend that misconception exists.

Let's also, for the sake of the article, assume that being a decadent lard-butt is not something to look down upon, but a lifestyle choice that should be commended. At least every once in a while. I mean, even vegetarians love to stuff themselves with delicious gooey cheese, cream, and carbs every once in a while, right?

If ultimate indulgence, supreme creaminess, and a ridiculous amount of tasty goo are what you're after, this recipe—a layered lasagna with mushrooms, seared Brussels sprouts, and plenty of cheese—is a good way to get you there. The mushrooms and Brussels sprouts? Yeah, they're in there too, but they are there entirely for the sake of pleasure. I add Brussels sprouts to my rib-stickers not because they're green and healthy, but because they're damn delicious. The green and healthy part is just an added bonus.

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First things first: I use no-boil lasagna noodles for pretty much all of my lasagna recipes. They're easier to assemble and I like their flat shape. The one problem? It's difficult to tell just how much liquid they're going to absorb if you use them completely raw in a dish. What looks like a nice sauce can end up dry by the time the lasagna finished baking. To solve this problem, I use a trick I learned from Cook's Illustrated: soak the noodles in water beforehand. By letting them soak for about 15 minutes in warm water, they hydrate, which prevents them from soaking up too much more liquid as they bake later on.

The Mushroom Duxelles

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While the noodles soak, we need to make mushroom duxelles, which is a fancy French word that roughly translates into "mushrooms that have been chopped and cooked with cream and aromatics into a paste with the kind of flavor that would make the more Victorian of your relatives convinced that to partake in it would bring grievous moral injury to the soul."

It starts by washing button mushrooms. (Forget what you've heard about 'shrooms absorbing water when you wash them. The amount they take up is a negligible amount close to 1%.)

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Next, you need to chop them. You can do it by hand (I like to crush them between my thumb and forefingers before giving them a good once over with a knife), but it's far easier to pulse them in a food processor in batches. A moderately rough chop is what you're looking for.

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Start cooking those chopped mushrooms with butter in a large skillet. The goal is to get them to completely lose their moisture and start browning. They'll get wet at first, then they'll eventually dry out and start to sizzle.

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Once the mushrooms have deepened in color, it's time to add aromatics: shallots, garlic, and picked thyme leaves are classic duxelles flavorings.

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Next, the heavy cream. Though duxelles are often cooked with a touch of brandy or cognac, I find the flavor gets a little too sweet and intense for the finished dish. I want the mushrooms to blend and meld with the other flavors.

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The cream will eventually cook down and tighten up, forming a mixture that is rich and almost paste-like. You're looking for a consistency that you can spread easily on a lasagna noodle. (And don't forget to season it!)

The Creamed Brussels Sprouts

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Next up: the sprouts. You can slice them by hand, but for this recipe, where I want them to really melt into the sauce, I prefer to use the grating dish of a food processor. (If you don't have one, you can patiently grate them on a box grater. Just watch your fingers).

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Finger shredding means less structure to break down and more surface area for browning, which adds that sweet, nutty flavor to the finished dish.

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You want to start by searing off those grated Brussels sprout leaves in oil, letting them char deeply before scraping them off the bottom of the pan and flipping them. Repeat this a few times until a good 50% of the sprouts have been charred before adding more cream.

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Once the cream reduces, it'll look like this. Pretty? No. Delicious? Sure is. And don't worry, it gets layered into the lasagna, where that drab brown color melds into the mix.

The Cheese Sauce

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Our last ingredient is a basic besciamella, or white cheese sauce. I make mine the classic way: butter and flour roux-thickened milk, to which I add nutmeg and grated mozzarella cheese.

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The key is to remove the sauce from heat as you add the cheese to ensure that it doesn't clump or break. Smooth, shiny, and gooey is what you're looking for here.

Assembly

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There's not too much rhyme or reason (not to be confused with thyme and season) when assembling a lasagna. There are three basic rules to remember: