Start by preheating your oven to 400°F (200°C). Roll out the pizza dough on a floured surface into a rectangle, about 12x16 inches, to ensure even filling distribution.

Spread 1/4 cup of pizza sauce evenly over the rolled-out dough, leaving a small border (about an inch) around the edges. Lay down 8 slices each of pepperoni, Genoa salami, and ham, ensuring they’re evenly distributed. Sprinkle 1/2 cup each of sliced black olives, green bell peppers, and red onions across the meat. Finally, top everything with 1 cup of shredded mozzarella cheese, 1/2 cup of shredded provolone, and 1/2 cup of grated Parmesan evenly on top.

Begin carefully rolling the dough from one long side to the other, forming a log. While rolling, tightly hold the fillings in place. Seal off the ends securely and pinch the seams shut to prevent any leaks during baking.

Place the Stromboli seam-side down on a baking sheet lined with parchment paper. Mix 1 tablespoon olive oil with 1 teaspoon dried oregano, 1/2 teaspoon garlic powder, and a pinch of salt and black pepper. Brush this mixture over the top of the dough. Use a sharp knife to make small slits for steam to escape. Finally, brush the log with a beaten egg for a golden, shiny finish. Bake for 20-25 minutes, or until the crust is beautifully golden brown.

Once baked, allow the Stromboli to cool for a few minutes. Slice it diagonally for clean cuts and prevent fillings from spilling out. Serve warm with your favorite dipping sauce, such as marinara or garlic butter.