Preheat oven to 450 degrees F.

Place ground sirloin in a large mixing bowl and punch a well into the center of meat. Fill well with the egg, bread crumbs, onion, garlic, red pepper flakes, Worcestershire, parsley, cheese, and a little salt and pepper. Mix up meatball ingredients until well combined, yet not over-mixed. Divide mix into 4 equal parts, roll each part into 4 balls and space equally onto a nonstick baking sheet. Place meatballs in oven and roast about 12 minutes. Break a meatball open and make sure meat is cooked through before removing from the oven.

Combine meatballs and sauce and pile into sub rolls, 4 meatballs per sub. Top with shredded cheese and place under subs under broiler to melt cheese.