Sauté the garlic, then add the mushrooms and cook over high heat until all the liquid evaporates and the mushrooms are golden. Soak the dried porcini mushrooms in a little water.

In a pot, combine the milk and flour, whisking well to avoid lumps. Add the sautéed mushrooms, then the soaked porcini mushrooms and their soaking water. Bring to a boil and cook until the béchamel thickens.

Assemble the lasagna in layers, generously adding ragù and béchamel to each layer. For the top layer, use only béchamel and mushrooms.

Sprinkle with grated Parmesan cheese and a pinch of ground red pepper. Bake at 400°F (200°C) for 35 minutes.