In a microwave-safe 2-cup measuring cup, combine pizza sauce and pepperoni. Cover with vented microwave-safe plastic wrap.
Microcook on 100 percent power (high) for 3 to 4 minutes or until heated through, stirring after 2 minutes.
Spoon over Speedy Microwave Potatoes. Sprinkle with mozzarella and Parmesan, if you like. Return to oven. Microcook for 2 to 3 minutes more or until the cheeses melt. Makes 4 servings.