Spring asparagus frittata is a light, elegant vegetarian Italian egg dish. This high protein mediterranean family meal is fresh, healthy, and perfectly suited to a clean eats lifestyle.
Preheat the oven to 375°F (190°C). Position a rack in the center.
Trim and cut the asparagus into 1-inch pieces. Dice the onion finely.
Heat olive oil in an oven-safe 10-inch skillet over medium heat. Add onions; sauté for 3–4 minutes until softened, then add asparagus and cook, stirring, for another 3–4 minutes until just tender-crisp.
In a large bowl, whisk eggs thoroughly. Stir in milk, Parmesan cheese, salt, and black pepper until well combined.
Pour the egg mixture evenly over the vegetables in the skillet. Reduce heat to low and cook undisturbed for 4–5 minutes, gently shaking the pan, until the edges begin to set but the center is still runny.
Transfer the skillet to the oven and bake for 10–12 minutes, or until the top is puffed and just set (center should not jiggle when gently shaken). Remove and let cool for 3 minutes before slicing. Serve warm or at room temperature.