Preheat the oven to 375°F.
Divide the pizza dough into 2 pieces.
Using your hands or a rolling pin, roll out each piece to make a circle. You may need to flour your surface and rolling pin a little to prevent sticking.
Place parchment paper on a baking sheet.
Transfer one calzone crust to the baking sheet to make calzone.
Place 4 meatballs on one side of the pizza crust. Cut up meatballs if they’re large.
Drizzle 1 tablespoon of marinara or pizza sauce on the pizza crust in the middle, keeping it away from the edges.
Sprinkle with mozzarella cheese
Fold over dough to make a half circle shape. Pinch edges together to seal then fold the pressed edges up toward the calzone and press again.
Whisk egg and water together to make an egg wash.
With a pastry brush, brush the egg wash on the outside of the calzone.
Sprinkle calzone with /18 teaspoon garlic salt and ¼ teaspoon of Italian seasoning.
Repeat with the next calzone.
Loosely tent calzone with foil so the foil doesn’t touch the tops of the calzones. Please in the oven and cook for 15 minutes. Remove the foil then cook for 15 more minutes until the crust is a deep golden brown.