Peel and chop the onions, then sauté them in a skillet with a drizzle of olive oil and a pinch of salt. When they're soft but not browned, add 1 cup (240 ml) of cold water and bring to a boil. Meanwhile, rinse the asparagus and break them into pieces with your hands, using only the tender parts. Once the water with the onions is boiling, add the asparagus and cook until tender. Turn off the heat and let cool slightly.

Pour a drizzle of olive oil into a nonstick skillet, heat it, then pour in the egg, asparagus, and onion mixture. Use a spoon or fork to gently move the edges so the liquid mixture can flow underneath as it starts to set. Cover with a lid and cook over low heat until the top is almost set. Turn off the heat and let it sit, covered, for about a minute so the top finishes setting.

At this point, flip the frittata using the lid, return it to the skillet, turn the heat back on, and brown the other side. If you want to skip this step, you can simply bake the frittata in a preheated oven at 350°F (180°C) for about 20 minutes.

Best regards,
Maria Grazia Trocini