Sloppy Joe Grilled Cheese Casserole Ingredients • 1lb lean ground beef • 1 yellow onion, diced • 1 cup ketchup • 1 tbsp Worcestershire sauce • 1/4 cup brown sugar • 2 tsp onion powder • 12 slices bread • 1/2 cup margarine • 4 cups mozzarella cheese, shredded Instructions 1. Preheat oven to 400F….