These apple-sausage meatball sandwiches are a delicious twist on the classic meatball sub. The meatballs are made with a combination of ground sausage and grated apple, giving them a sweet and savory flavor. They are then simmered in a tangy tomato sauce until tender and juicy. The meatballs are served on a toasted sub roll with melted cheese and topped with additional sauce for a satisfying and flavorful sandwich.