1 lb. med. shells
1 lb. hamburger
1 onion, cut up
1 (15 oz.) jar chunky Ragu
1 lg. can crushed tomatoes
1 sm. can mushrooms
Oregano
Garlic powder
8 oz. provolone cheese, cut up
8 oz. shredded mozzarella
2 c. sour cream
1/4 c. Parmesan cheese

Cook hamburger and onions; add sauce, tomatoes, mushrooms, garlic and oregano. Simmer 30 minutes. Cook shells; drain. Mix cheeses and sour cream with shells. Layer shell mixture and sauce. Bake at 350 degrees for 30 minutes.