Clean or peel the onion, garlic, carrot and celery, chop them in cubes. Heat the oil, fry the vegetables and meat. Cover with tomatoes and Bay leaves and cook for 30 minutes, stirring occasionally. Remove Bay leaf, season with salt, pepper and a pinch of sugar.

Heat the milk and butter. Add the flour, mix with the blender and cook for 2 minutes. Remove from heat, put half of the Parmesan.

Preheat the oven to 200 °. Line a large, oven proof dish with lasagne sheets, spread one third of meat sauce on it, give some Bechamel sauce over it. Continue layering the rest, add the lasagna sheets and Bechamel sauce. Sprinkle with remaining Parmesan cheese. Bake in the oven (center, air circulation 200 °) for 30 minutes.