Preheat the oven to 400 degrees F. Grease an 8-inch round cake pan with cooking spray.
Unroll the crescent dough onto a clean surface. Use a rolling pin to go over the dough a couple of times and stretch it a bit into a large rectangle. Line the dough with the pepperoni. Top evenly with the broccoli and sprinkle with garlic salt. Top with an even layer of mozzarella.
Roll the dough from one side to the other. Use a sharp knife to cut into seven 1-inch rounds. Put the rounds in the prepared cake pan, crowding them together. Bake until golden brown, 25 to 30 minutes. Sprinkle with the Parmesan and let stand 5 minutes before serving.