Place the 12 frozen meatballs on a microwave safe plate. Thaw for about 30 seconds, turn over and thaw for another 30 seconds.
Then place the meatballs in a skillet with 1 1/2 cups marinara sauce. Cook on medium high heat until the meatballs are heated through and covered in sauce.
While the meatballs are simmering, cut the rolls in half leaving them attached.
Place the bottom section of the rolls in a lightly greased 9 x 13 inch pan. Set a heated meatball that is covered in marinara sauce on each roll. Sprinkle mozzarella cheese and Parmesan cheese over all of the meatballs. Place the top part of the rolls on top (they should still be attached to each other).
Combine the melted butter, garlic salt and Italian seasoning together in a small bowl.
Baste the top of the rolls with the buttery mixture. Then sprinkle with grated Parmesan cheese.
Cover the pan loosely with foil and bake for 8 minutes.