Preheat oven to 375°. In a large bowl, combine mozzarella, ricotta, 1/2 cup grated Parmesan cheese, pepperoni, 1 egg, garlic powder, 1/2 teaspoon Italian seasoning and, if desired, crushed red pepper flakes; set aside.
Divide bread dough into 16 pieces. On a lightly floured surface, roll each portion into a 5-in. circle. Place 1 teaspoon pizza sauce and 1/4 cup filling in center of each circle. Lightly brush edge of dough with water. Bring dough over filling; press firmly, then pinch or crimp seams to seal.
Place on greased or parchment-lined baking sheets. Lightly beat remaining egg; brush over pockets. Sprinkle with remaining 3 tablespoons grated Parmesan cheese and 1/4 teaspoon Italian seasoning. Bake until deep golden brown, 20-25 minutes. Allow to cool 2-3 minutes before serving. If desired, serve with additional pizza sauce.