Preheat the oven to 375°F (190°C) and lightly grease a baking sheet.
Unroll the pizza dough onto a lightly floured surface and stretch it into a 12x16 inch rectangle.
Evenly spread the pizza sauce over the dough, leaving a 1/2 inch border around the edges.
Sprinkle 1 1/2 cups of mozzarella cheese over the sauce.
Scatter the quartered beef pepperoni slices over the cheese.
Sprinkle the Parmesan cheese and red pepper flakes (if using) over the pepperoni.
Starting from one of the long edges, tightly roll the dough into a log and pinch the seam to seal it.
Slice the log into 1-inch thick slices.
Arrange the roll-ups on the prepared baking sheet, cut-side up, making sure to leave space between each.
In a small bowl, whisk together the remaining 1/2 cup of mozzarella cheese, olive oil, garlic powder, and dried oregano.
Spoon the cheese mixture evenly over the roll-ups.
Brush the tops of the roll-ups with the beaten egg.
Bake for 20-25 minutes, or until golden brown and the cheese is melted and bubbly.
Allow to cool for a few minutes before serving. Serve warm with extra pizza sauce for dipping.