Spaghetti casserole is a delious, hearty meatless pasta recipe which is a combination of spaghetti and lasagna ingredients. The main ingredients of spaghetti casserole are spaghetti, butter, meatless spaghtti sauce, parmesan cheese, tomatoes, mushrooms, basil, oregano and mozzarella cheese. A variation to the spaghetti casserole can be made by adding ground beef, fat-free milk to it.