Roll the pizza crust on a flat surface. Use a rolling pin to thin it out into a rectangle and use a pizza cutter to cut the center both horizontally and vertically, creating four smaller rectangles.

Cut the thawed meatballs in half.

To one side of each piece of dough add some meatballs, mozzarella, parmesan, garlic powder, Italian seasoning, and crushed red pepper flakes. Fold the empty side over the filled side and press the seams shut. Use a fork to press down on the seams to make sure they don't open during baking.

Place the calzones on a lined baking sheet. Mix the melted butter with more garlic powder and Italian seasoning and brush over each calzone.

Bake in a 400 degree oven for 14 to 18 minutes. Remove from the oven when the crust is cooked how you prefer.

Serve with more parmesan cheese over top if desired and with the pizza or marinara sauce for dipping.