Heat the olive oil in a pan. Add the onion, and lightly stir fry for a couple of minutes. Add the artichokes, asparagus and peas, add salt and pepper, and let cook, half covered, for 15 minutes. If the vegetables start to stick to the bottom, add a splash of water (just make sure it is fully evaporated when the vegetables are cooked). After this time, add the spinach, and cook for 5 more minutes. Check for salt, and add a little more if they seem bland.
in a bowl, whisk the eggs with the milk, and a small pinch of salt and pepper. Add the cheese and, if using, the saffron, dissolved in a tbsp of warm water. Whisk briefly to incorporate all the ingredients. Add the cooked vegetables to the eggs and whisk to incorporate.
Heat a cast-iron or ovenproof skillet that will make your frittata about 1 inch thick. Greasing it beforehand will help prevent sticking. Pour the frittata mixture in the pan, and let the bottom set for a minute. Transfer to the oven and bake until cooked and lightly brown on top, about 15 minutes. Check the top with your finger and, if it does not seem to collapse when pressed, it is ready. You can also check with a knife if there is still runny egg in the center. Try to not overcook it! If you are not 100% sure it is done, it is better to take it out of the oven 5 minutes early rather than late.
Serve with a salad on the side, some simple grains, with a good slice of garlic bruschetta, or use it to stuff a sandwich!
24 Year old Italian web dev, Graphic and UI designer who, like many designers, got seduced by food photography. I talk to way too many random people when in New York and to way too many random animals when I'm in the Italian countryside.
I run hortuscuisine.com, a blog about Italian, natural vegetarian cooking.