Preheat the oven to 375 degrees . Line a baking sheet with parchment. On a floured work surface, stretch the pizza dough into a 10-by-14-inch rectangle; transfer to the prepared baking sheet. Spread the pasta sauce over the dough, leaving a 1-inch border. Layer the ham, red peppers and cheese over the sauce.
In a bowl, beat the egg with 1 tbsp. water. Using a pastry brush, paint 1 long edge of the dough with the egg wash. Starting at the opposite long end, roll up the dough; pinch the edges to seal. Position the stromboli seam side down on the baking sheet. Brush with the remaining egg wash.
Bake the stromboli until golden-brown, about 30 minutes. Let cool on the baking sheet for 15 minutes. Slice into 1-inch pieces and serve warm.