French Onion Mozzarella Stuffed Meatballs are a delicious twist on traditional meatballs. These meatballs are made with a mixture of ground beef, breadcrumbs, and French onion soup mix, then stuffed with gooey mozzarella cheese. They are baked until golden and cooked through, then served with a rich and flavorful French onion gravy. These meatballs are perfect as an appetizer or served over pasta for a satisfying main course.