In a small saucepan, heat the milk over very low heat without bringing it to a boil.

In a skillet, preferably non-stick, melt the butter over low heat.

Add the sifted flour all at once, whisking continuously to prevent lumps from forming.

Cook until the mixture is homogeneous and golden in color.

Once the color of the mixture begins to turn golden, slowly whisk in the milk and continue whisking until it reaches a thick, creamy consistency characteristic of béchamel sauce. To test if it is done, dip a spoon in the sauce — when it coats the spoon, it is ready.

Season with salt, nutmeg, and pepper. The béchamel sauce is now prepared.

In a skillet, heat the oil and minced garlic.

Add the mushrooms and cook until all the liquid has evaporated.

Season with salt and pepper to taste, then set aside.

Place a few spoonfuls of mushrooms on the bottom of a lasagna pan (about 30×20×4 cm).

Lay a pasta sheet over top, spread with béchamel sauce, distribute more mushrooms, cubed mozzarella, and sprinkle with grated Parmesan cheese.

Continue layering in this manner until all ingredients have been used, or the pan is full. Top with more Parmesan cheese.

Cover the pan with aluminum foil and bake in a preheated 200 °C (392 °F) oven for approximately 30 minutes.

Remove the foil and continue baking for another 15–20 minutes, or until the pasta is soft when pierced with a fork and the top is nicely browned.

Remove from oven and let rest for 10 minutes before serving the hot and creamy mushroom and mozzarella lasagna!