Procedure for Bolognese sauce: Chop finely the carrot, the celery and the onion. Heat a pan and sauté them with a little of olive oil. Add the mixed minced meat, the bay leaf and stir. Once the meat has reached a brown colour pour the wine and let reduce. Add the tomato paste, cover with water and let cook for at least 30 minutes. Season with salt and pepper, remove the bay leaf and set aside. Clean the mushrooms, slice them finely and cook in a Teflon pan over a medium heat. Set aside.
Procedure for Béchamel sauce: In a pot melt the butter, add the flour and then pour the milk stirring constantly to avoid lumps. Season with salt and a little nutmeg then bring to boil. cook for only a couple of minutes. Set aside.
Assembly: Grease a baking tray with a little bit of butter and spoon over the bottom a first layer of béchamel and Bolognese sauce. Create the first layer with the Lasagne sheets, then cover it with some mushrooms slices and sprinkle with grated parmesan.
Repeat this procedure 5 times, altering layers of Bolognese sauce, Lasagne, mushrooms and béchamel Make sure to leave enough béchamel sauce to cover completely the top layer.
Bake in a preheated oven at 220 °C for 25-30 minutes.
Let the Lasagne rest for ten minutes before serving.