Preheat the oven to three hundred seventy five degrees Fahrenheit and line a baking tray with parchment paper.
Unroll the croissant dough and separate it into triangles. Add mozzarella cheese and pepperoni to the wide end of each triangle.
Roll the dough from the wide end toward the tip to form croissant rolls and place them seam side down on the baking tray.
Brush each roll with melted butter and sprinkle with garlic powder, Italian seasoning, and Parmesan cheese if using.
Bake for twelve to fifteen minutes until golden brown and flaky. Allow to cool slightly before serving.