2 garlic cloves, minced
juice of half a lemon
Begin by spraying the bottom and sides of a deep lasagne pan. Spread a thin layer of bechamel in bottom of pan. Place a layer of pasta sheets on top of bechamel, overlapping slightly. Cover with mushrooms, then another layer of bechamel. Spread a little of the two cheeses over. Make another layer of pasta. Spread spinach over, then a layer of bechamel. Sprinkle with cheese. Repeat with another pasta layer, topping with tomato and onion mixture. Pour bechamel over, sprinkle with cheese. Add a final layer of pasta, repeating the bechamel and ending with sprinkled cheeses. Dot top with a little butter. Bake about 20 minutes covered with foil, in a 400 degree oven. Uncover and bake 10 minutes to brown, watching to make sure it doesn't burn.
Let stand 5 minutes before cutting to serve.