Makes One Lasagna
Directions
Clean your mushrooms by brushing them gently with a towel or a pastry brush. Trim the stems and slice the mushrooms.
Heat two tablespoons of butter with the olive oil in a large skillet. Add the mushrooms to the pan. Leave them without turning until they are lightly browned on one side. Season with a little salt and pepper. Stir and continue cooking until soft. Remove to a bowl. Add the onion to the pan. Season the onion with a little salt and pepper. Cook the onion until lightly browned and caramelized. Remove to the bowl with the mushrooms.
Heat the milk in a heat-safe, four-cup measuring cup in your microwave or in a pot on your stove. Melt eight tablespoons of butter in a saucepan over medium heat. Add the flour to the melted butter and cook for about a minute. Add the hot milk to the butter mixture, stirring to combine. Season with two teaspoons of salt, one teaspoon of pepper, and the nutmeg. Stir and keep cooking until the sauce thickens. You'll be able to draw a line through the sauce on the back of your spoon when it is ready. Remove the sauce from the heat.
Cook sixteen lasagna noodles according to the package directions. Spread a few spoonfuls of sauce in the bottom of your lasagna pan. Spread four lasagna noodles over the sauce. Add a layer of sauce to the noodles. Spread one-third of the mushroom and onion mixture over the sauce. Sprinkle with 1/4 cup of Parmesan cheese. Complete two more layers of noodles, sauce, mushroom mixture, and Parmesan cheese. Top with a final layer of noodles, sauce and Parmesan cheese.
Bake the lasagna in a preheated 350 degrees F oven for approximately 45 minutes or until browned on top and bubbly. Let sit for 20 to 30 minutes before serving.