1 lb. ground chuck
1 lg. onion, chopped
1 clove garlic, crushed
8 oz. Mozzarella cheese, shredded
1/2 c. Italian dry bread crumbs
1/4 c. parsley
1 egg
Salt and pepper
18 giant shells, partially cooked
2 (15 oz.) jars spaghetti sauce
1/4 c. dry red wine vinegar
1/2 c. grated Parmesan cheese

Brown chuck, onion and garlic; drain. Stir in cheese, crumbs, parsley, and egg. Stuff shells. Spoon 1/4 sauce in 9x13 pan. Place 1 layer shells and spoon rest of sauce over; sprinkle with grated cheese and bake at 400 degrees for 25 minutes. Serve with added grated cheese.