8 oz. box shell pasta
2 lbs. ground beef
2 med. onions, chopped
1 garlic clove, crushed
1 (14 oz.) jar spaghetti sauce
1 (3 oz.) jar sliced mushrooms
1 1/2 c. sour cream
1 pkg. Provolone cheese, sliced
1 pkg. Mozzarella cheese, sliced

Brown ground beef; drain. Add onions, garlic, spaghetti sauce, mushrooms. Simmer 20 minutes. Cook shells according to directions. Drain and rinse shells. Pour half of shells into a large casserole dish. Cover shells with half of meat mixture; spread with half sour cream. Cover with Provolone cheese. Repeat these layers, topping with Mozzarella cheese. Cover. Bake at 350 degrees for 40 minutes. Remove cover and bake until cheese is melted and lightly brown.