Ingredients (serves 4)
2 tablespoons unsalted butter
1/3 cup diced onions
1/2 teaspoon salt
500g asparagus, tough ends snapped off, spears cut diagonally into 25mm lengths
6 large eggs, lightly beaten
1 cup shredded cheddar cheese
Heat butter into a 10-inch oven-proof frying pan over medium-high heat. Add onions and cook, stirring occasionally, until they soften and turn translucent, about 3 minutes. Add asparagus, reduce heat to medium-low, and cook, covered, for 3 minutes.
Pour in eggs and cook until almost set, but still runny on top, about 2 minutes. While cooking, pre-heat oven broiler.
Sprinkle cheese over eggs and put in oven to broil until cheese is melted and browned, about 4-6 minutes. Remove from oven with oven mitts and slide frittata onto a serving plate. Cut into wedges.