This isn't spaghetti, but it is one of my kids' favorites. You can either make it all together in one pot, or do as I do and layer it in a 9 x 13" pan. Yummy!
Pasta and Cheese in a Pot
1 lb. box medium shells
32 oz. any kind of spaghetti sauce
1 med. to lg. onion, chopped
1 - 2 lb. lean ground beef
1 pt. sour cream
1 garlic clove, crushed
1/2 lb. sliced mozzarella cheese (I use more)
1/2 lb. sliced provolone cheese (I use more)
Brown ground beef in a lg. deep frying pan, and drain excess fat. Add onion, garlic, spaghetti sauce (I also add canned or previously sauteed mushrooms here, too). Mix and simmer 20 min. or until onions are soft. In the meantime, cook pasta shells until they are al dente. They will finish cooking later. Drain. Pour half the shells into deep casserole, cover with half the sauce mixture. Spread half the sour cream over the sauce, and top with the provolone. Repeat layers, ending with mozzarella. Cover and bake at 350° for 35-40 minutes. Remove cover and bake until cheese melts and slightly browns. I know the sour cream sounds strange, but it really works. This can be made in advance and it is yummy as leftovers.