Preheat oven to 375°F (190°C) and line a baking sheet with parchment paper.
- Roll pizza dough into a 10×14-inch rectangle on a lightly floured surface.
- Spread pizza sauce evenly over dough, leaving a 1-inch border.
- Sprinkle mozzarella cheese evenly over sauce.
- Arrange pepperoni slices in a single layer over cheese.
- Sprinkle with Italian seasoning and garlic powder, if using.
- Roll dough tightly from a long edge into a log, pinching seam and ends to seal.
- Place seam-side down on prepared baking sheet.
- Brush with beaten egg, and sprinkle with parmesan and/or red pepper flakes if desired.
- Bake 25–30 minutes, until golden brown and cooked through.
- Cool slightly, slice into 6–8 pieces, and serve with extra sauce for dipping.