3) Pour the egg mixture over the asparagus mixture and cook for a few minutes until the eggs start to set. Sprinkle with cheese. Reduce heat to medium-low and cook until the frittata is almost set but the top is still runny, about 2 minutes. Place the skillet under the broiler. Broil until the top is set and golden brown on top, about 5 minutes.
4) Let the frittata stand 2 minutes. Using a rubber spatula, loosen the frittata from skillet and slide the frittata onto a plate.