There isn't a meatball on the planet that I'll shy away from, and I'm always game for a new version. Enter these meatballs, which are packed with mozzarella, making them quite the party surprise. Meatball sandwiches are easy to prepare. They're a crockpot's best friend and a great way to have a meal ready when you walk in the door. They're also a handy party food, easy to stab with a toothpick yet satisfying. This meatball recipe is cheese-stuffed, and when has cheese-stuffed anything let you down before?