A meatball sub is a type of sandwich that features meatballs as the main filling. Typically, the meatballs are made from ground meat, such as beef or pork, mixed with breadcrumbs and seasonings. They are usually cooked in a savory tomato sauce and served in a long, soft bread roll, often called a sub or hoagie. To enhance the flavor, meatball subs are often topped with melted cheese, such as mozzarella or Parmesan. This sandwich is popular in many regions, especially in Italian-American cuisine, and is enjoyed for its hearty and comforting qualities.