Gma Kay's Cheesy Pasta-in-a-Pot

Why I Love This Recipe
If you like a bowl full of cheesy pasta this one's for you - delicious!
Ingredients You'll Need
2 lbs ground beef or turkey
2 onions, chopped
1 clove garlic, crushed
1 jar (14 oz) spaghetti sauce
1 can (1 lb) tomatoes (I like crushed)
1 can mushrooms
8 oz shell macaroni
1 1/2 pints sour cream
1 pkg sliced provolone
1 pkg sliced mozzarella
Directions
Cook ground beef or turkey until brown, drain fat. Add onion, garlic, spaghetti sauce, tomatoes, and undrained mushrooms. Mix well; simmer for 20 minutes or until onions are soft. Meanwhile, cook pasta shells, drain and rinse in cold water. Pour half the shells into a deep casserole (a large 6-8 inch deep skilled - a Dutch Oven works great). Cover with half the meat sauce. Spread half the sour cream over the sauce; top with slices of provolone. Repeat layers. End with slices of mozzarella.
Cover the casserole and bake at 350° for 35-40 minutes. Remove the cover and continue baking until mozzarella melts and browns slightly.