This is a recipe I found that was tweaked by a lady that got it somewhere - and now I've tweaked it again. I adore mushrooms, so I use a lot, you can make it to your liking. Makes a lot of dish cleanup, but it's worth it!
Preheat oven to 375°F. Bring a large pan of water to boil with salt. Add the lasagna noodles and cook for 10 minutes. Drain and set aside. You can also use the ready for oven no boil lasagna noodles if you'd like and save a pot!
For the 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 butter in a large saucepan. 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, stirring until combined. Once you’ve added half of it, add the second half all at once, along with 1 1/2 teaspoons table salt, the pepper, and nutmeg. Cook over medium-low heat, stirring or whisking frequently, for 3 to 5 minutes, or until thick. Set aside.
Mushrooms: Slice mushrooms 1/4-inch thick. Heat 2 tablespoons olive oil and 2 tablespoons butter over medium heat in a large sauté pan. Cook the mushrooms with a couple pinches of salt for about 5 minutes, or until they are tender, tossing to make sure they cook evenly.
Assembly: Spread some of the sauce in the bottom of a 9 x 13 baking dish. Arrange a layer of noodles on top, then more sauce, 1/3 of the mushrooms and 1/2 cup grated parmesan and asiago. Repeat two more times then top with a final layer of noodles, your remaining sauce and the last of cheeses.
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.