1Preheat oven to 350 degrees F (175 degrees C). Spray a large baking sheet with cooking spray and sprinkle lightly with cornmeal.
2Roll pizza dough on a floured work surface into a 9x12-inch rectangle.
3Mix spaghetti with spaghetti sauce in a bowl until pasta is coated. Spread spaghetti and sauce down the center of the dough rectangle, leaving about 1 inch at the top and bottom uncovered. Spread meatballs in a line down the center of the spaghetti. Sprinkle mozzarella cheese over spaghetti and meatballs. Roll the dough over the filling, starting at a long edge. Pinch ends and seam tightly closed. Transfer roll to the prepared baking sheet.
4Bake in the preheated oven until crust is browned and filling is hot, 20 to 25 minutes. Brush roll with melted butter and sprinkle with garlic salt. Serve warm or cold.
Footnotes
Tip
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.