Cook macaroni as directed on package. Brown ground beef and onion in skillet; drain. ... Spread the shredded Mozzarella cheese on top, then sprinkle ... until cheese is melted.
Preheat oven to 350 degrees. ... Reserve 2 tablespoons Mozzarella cheese. In another bowl, combine ... plastic wrap place beef mixture. Top with another piece ... remaining warmed marinara sauce.