Leftover Beef Casserole II 2 cups diced cooked beef 1 can beef gravy or 1 cup of gravy made from dry mix 16-oz small white onions, drained 10-oz pkh frozen peas and carrots, cooked 1/2 cup shredded sharp cheddar cheese Combine meat with gravy, onions, peas and carrots. Transfer to casserole and top with shredded cheese. Bake at 350° for 35 minutes.