Heat the oven to 405.
Make the garlic butter. Lightly melt the butter in a small bowl, then stir in the garlic powder, onion powder, oregano and a pinch of white pepper.
Stretch the dough. Take half the dough ball and stretch it into a rectangle with your hands, no rolling pin needed. If it springs back, let it rest ten minutes and try again.
Brush and layer. Brush the garlic butter over the dough. Layer on the presliced mozzarella, then the pepperoni, then the shredded mozzarella. Leave a border at the edges.
Roll it. Tuck the sides in, roll it up, and set it seam-side down on the baking sheet.
Egg wash. Beat the egg with a splash of water in the same bowl the butter mix was in, and brush it over the outside.
Finish the top. Scatter chopped parsley and a light pinch of sea salt crystals.
Bake 22 to 25 minutes, until golden brown.
Rest 5 to 10 minutes, then slice with a sharp chef knife into rounds about 1.5 to 2 inches thick. Serve with warm marinara.