Step 1

Heat your oven: To 375°F.

Step 2

Prepare noodles: Bring a large, wide (if you use a wide one, you can save a dish later and saute your mushrooms in the bottom of it) pot of water to boil with salt and a splash of oil, that will help keep your noodles from sticking together as they drain. Add the lasagna noodles and cook for 10 minutes. Drain and set aside.

Step 3

Make béchamel: Bring the milk and garlic to simmer in a saucepan, or heat it in your microwave, and set it aside. Melt 1/2 cup (8 tablespoons or 115 grams) butter in a large saucepan. If your name is Deb, you will probably brown this butter, too. Add the flour and cook for one minute over low heat, stirring constantly with a whisk or wooden spoon. Pour in the hot milk, a little at a time at first and stirring until combined. Once you’ve added half of it, you can add the second half all at once, along with 2 teaspoons kosher salt, the pepper, and nutmeg. Cook over medium-low heat, stirring or whisking frequently, for 3 to 5 minutes, or until thick. Set aside.

Step 4

Prepare mushrooms: Discard portobello mushroom stems and/or trim the ends of the cremini stems. Slice mushrooms 1/4-inch thick. Heat 2 tablespoons olive oil and 2 tablespoons butter over medium in the bottom of the large, wide pot you used to cook the noodles earlier, or in a large sauté pan. Cook half the mushrooms with a couple pinches of salt for about 5 minutes, or until they are tender and release some of their juices, tossing to make sure they cook evenly. Repeat with additional oil and butter, and remaining mushrooms.

Step 5

Assemble lasagna: Spread some of the sauce in the bottom of an 8 x 12 or 9 x 13 baking dish. (Ina recommends the former, I only had the latter; if you’d like to freeze or give this dish as a gift, remember to use a foil pan). Arrange a layer of noodles on top*, then more sauce (about 1/4 of what remains), 1/3 of the mushrooms and 1/4 cup grated parmesan. Repeat two more times then top with a final layer of noodles, your remaning sauce and last 1/4 cup of parmesan.

Step 6

Bake: For 45 minutes, or until top is browned and the sauce is bubbly. Let sit at room temperature for 15 minutes before serving. To freeze for future use, allow it to cool completely and wrap two to three times in plastic wrap before freezing.