Yields: 8 servings
1 (9-ounce) package pre-cooked lasagna sheets
2 yellow onions, thinly sliced
1 sprig fresh thyme, coarsely chopped
4 tablespoons canola oil (or any neutral oil)
40 ounces crimini mushrooms, sliced lengthwise
½ teaspoon nutmeg
1 (25.5-ounce) jar tomato sauce
1½ cups mozzarella cheese
2 tablespoons Parmesan cheese
6 tablespoons unsalted butter
2 tablespoons bread crumbs, ground into a fine powder
¾ cup all-purpose flour
4½ cups milk, warm
1 tablespoon salt
1¼ teaspoons black pepper, freshly ground
1 cup sweet basil leaves, freshly snipped
Preparing the onions: Heat the olive oil in a large pan. Add 1 onion and thyme and cook over medium-low heat, stirring occasionally, for 8 to 10 minutes, until the onions are softened. Add the soy chorizo and tomato sauce. Bring to a boil, then turn off the heat. Season with salt and pepper. Set aside.
Cooking the onions and mushrooms: In a deep, non-stik saucepan, heat the olive oil. Add the remaining sliced onions. Cook until nicely golden and tender (it may take up to 5 minutes). Add the garlic. Cook for a minute, then add the mushrooms. Sauté until softened. Transfer to a plate, leaving as much oil as possible in the saucepan. Let cool. Some liquid from the mushrooms will be at the bottom of plate. Set aside.
For the béchamel sauce: In a saucepan, melt the butter over medium-low heat; you don't want it to burn. Bring the heat back up to medium-high (the butter should be hot and golden) and add the flour. Keep stirring manually with a whisk for approximately 3 minutes. The flour should absorb the butter and form a paste. Add the milk in 3 stages and stir well until fully incorporated. Increase the heat while constantly stirring for about 5 minutes. Reduce the heat to low. Add ½ cup each of mozzarella and nutmeg. Season with salt and pepper. Add the liquid from the mushrooms if the sauce is too thick (I did). Let cool.
Check the consistency of the béchamel sauce. If it's too thick, thin the sauce with the mushroom liquid (up to 1 cup).
In a 10” x 14” x 3” high rectangular pan sprayed with oil (for easy clean up), spread a layer of reserved onions and the tomato sauce first, then layer 4½ sheets of the lasagna. Spread a layer of mushroom mixture evenly. Sprinkle with mozzarella cheese and a few tablespoons chopped basil. Spread 2 to 3 ladles of the béchamel sauce, then add another 4½ sheets of lasagna. Repeat the same layers until all the ingredients are used up. Finish with the rest of the béchamel sauce. It should cover the whole tray; top with the remaining mozzarella cheese.
Sprinkle with Parmesan cheese and bread crumbs and place in the oven for 30 minutes at 375°F (until golden brown).
When it's cooked, remove the pan from the oven and let it rest for at least 20 minutes. Cut into squares.
I prefer using dry lasagna sheets. I use Barilla brand lasagna that's already pre-cooked. The heat and moisture of the béchamel sauce will cook and soften the lasagna sheets. I think it's better to control the level of liquid and to produce a denser consistency. You definitely don't want soggy lasagna! When you use dry pasta, you'll get good results and you'll also save some time.