Preheat and oven to 375 degrees. In a large bowl, combine the ground sirloin with all the seasonings and parmesan cheese.
Form the meatball mixture into 12 portions (2-inch meatballs) and us your thumb or knuckle to press an indentation down into each one. Slice 6 mozzarella balls into 12 pieces and place 1 piece in the center of each meatball.
Roll each meatball into shape around the mozzarella and place them in a large sheet tray lined with aluminum foil or parchment paper. Slice 6 pieces of prosciutto into 12 squares. Wrap each piece of prosciutto around a meatball, placing the seams of the prosciutto under the bottom. It’s okay if the prosciutto doesn’t completely wrap around because it shouldn’t come loose in the oven.
Bake the tray of meatballs for 25-30 minutes, no flipping or rotating required. Enjoy while hot and the cheesy centers are gooey!