Pre-heat oven to 450 degrees.
Heat 1 Tbsp olive oil in a large saucepan over medium heat. Add brussels sprouts to pan and season with salt and pepper. Sauté for about 3 minutes. Add garlic and sauté for 3 more minutes.
On a lightly floured surface, roll dough out into a thin 12-inch round. Transfer round to a foil-covered 12-inch pan. Brush dough lightly with remaining Tbsp olive oil.
Lay mozzarella cheese on dough, sprinkle on pancetta, and top with brussels sprout and garlic mixture and red pepper flakes (if using).
Bake for 12-15 minutes, until edges of flatbread are turning golden. Remove from oven and top flatbread with parmesan cheese shavings.
Slice and serve.