Step 1: Prepare the Dough

1. Preheat your oven to 400°F (200°C). If using homemade dough, let it rise according to your recipe instructions.
2. On a lightly floured surface, roll out the pizza dough into a rectangle (about 12×16 inches).

Step 2: Cook the Filling

1. In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the sliced onion and bell pepper, cooking until softened (about 5-7 minutes). Add the minced garlic and cook for an additional minute.
2. Push the vegetables to the side of the skillet. Add the thinly sliced steak to the skillet and season with Italian seasoning, salt, and pepper. Cook until the steak is browned and cooked through (about 3-5 minutes). Remove from heat and let cool slightly.

Step 3: Assemble the Stromboli

1. Spread the cooked steak and vegetable mixture evenly over the rolled-out dough, leaving a border around the edges. Sprinkle the shredded mozzarella cheese evenly over the top, followed by provolone and Parmesan cheese if using.
2. Starting from one long edge, carefully roll the dough over the filling, tucking it in as you go to create a tight roll. Pinch the edges to seal and tuck the ends under to secure the filling.

Step 4: Prepare for Baking

1. Transfer the rolled stromboli to a parchment-lined baking sheet, seam side down.
2. In a small bowl, whisk together the beaten egg and water. Brush the egg wash over the top of the stromboli. Make a few slits on top for steam to escape.

Step 5: Bake the Stromboli

1. Bake in the preheated oven for 15-20 minutes, or until the stromboli is golden brown and cooked through.
2. Remove from the oven and let cool for a few minutes before slicing.

Step 6: Serve

1. Cut the stromboli into slices and serve warm with marinara sauce for dipping if desired.