04Sprinkle the remaining 1/3 cup Parmesan over the top.
05(If the skillet handle is plastic, wrap it in a double thickness of foil.) Broil the frittata under a preheated broiler about 4 inches from the heat for 3 to 4 minutes, or until the cheese is golden, let it cool in the skillet for 5 minutes, and run a knife around the edge.
06Slide the frittata onto a serving plate, cut it into wedges, and serve it warm or at room temperature.