Spinach Frittata

1. Position the rack under a broiler about 4 inches from the heat source and turn it to high. Crack the eggs on a fl at, hard surface and open them into a bowl. Add the cheese, sprinkle with some salt and pepper, and whisk until the yolks and whites are just combined.
2. Put 1 tablespoon of the olive oil in a medium ovenproof skillet, preferably nonstick, over medium-high heat. When it’s hot, add the onion, sprinkle with salt and pepper, and cook until soft, 3 to 5 minutes.
3. Add the spinach and cook, stirring and tossing frequently, until the leaves wilt and release their liquid; lower the heat if necessary to keep everything from burning. Once the spinach starts to dry and stick to the pan, after 3 to 5 minutes, turn the heat to low. Cook, stirring occasionally, until there is no water left in the pan and the spinach is coated in oil, another minute or so, then spread out the spinach in the pan.
4. Pour the egg mixture over the spinach and onions, evenly distributing the vegetables if necessary. Cook, undisturbed, until the eggs are firm at the bottom and the top is still runny, 8 to 10 minutes.
5. Put the pan under the broiler until the eggs finish setting and brown lightly, 2 to 4 minutes, watching to make sure the frittata doesn’t burn. (Be careful removing the pan from the oven since the handle will be hot.) Cut the frittata into wedges and serve right away, or warm, or at room temperature.

—Recipe from How to Cook Everything: The Basics