After crust has been removed from oven, spoon sauce over crust. Top with 1-1/2 cups mozzarella, sausage and peppers. Sprinkle over remaining 1/2 cup mozzarella. Bake 12 to 15 minutes longer or until cheeses are melted and crust is well-browned. Remove stone to cooling grid; let cool slightly. Top with crushed red pepper, if using; serve warm.