In a medium bowl combine ground beef, onion, garlic, parsley, salt and pepper. Mix gently to combine without overworking the meat. Make 12 meatballs from the mixture. (3 good size meatballs for each hoagie roll). (Adjust accordingly for more or less sandwiches).

In a medium saucepan heat pasta sauce, covered.

Over medium heat, cook the meatballs in a large skillet, uncovered, adding a small amount of water to the bottom of the skillet. Turn meatballs frequently to avoid burning, adding small amounts of water as necessary. Cook meatballs until no longer pink in center.

Once meatballs are done, transfer to saucepan with sauce. Let simmer while you prepare the hoagie rolls.

To prepare hoagie rolls: Do not slice completely through the hoagie rolls. Leave a sort of pocket to cradle the ingredients. In each hoagie roll, place 2 slices of Provolone in the crease of the roll. Top with 3 meatballs and a bit of sauce. Sprinkle shredded Mozzarella cheese over top of meatballs. Grate Parmesan cheese over top of subs, if desired.

Serve hot.