Sausage and spinach stuffed shells is a kid-friendly meal. Onions are sauteed with sausage and garlic before being combined with spinach and ricotta cheese. Each shell is filled to the brim with the mixture and topped with tomato basil cream sauce and plenty of fontina cheese. If you don't have shells, this filling would also work for manicotti. Sausage and spinach stuffed shells will please children and adults alike.