How to cook
The zucchini, potatoes and tomatoes are cut into circles, they're seasoned with salt and butter, then arranged in a clay baking dish.
In a saucepan, prepare the Béchamel sauce. Put the oil to heat up and fry the flour in it and after a short while add the milk.
Stir until the sauce thickens and becomes smooth, season it with salt, black pepper and basil and then remove it from the heat.
Pour the prepared Bechemel sauce over the vegetables and sprinkle them with the grated yellow cheese. Bake the casserole in a moderately heated oven.