Mustard Green-and-Sweet Onion Frittata

1. 1

   Preheat the oven to 350.

2. 2

   In a large ovenproof nonstick skillet, heat 1 tablespoon of the oil.

3. 3

   Add the onion and cook over moderately high heat until golden brown, 10 minutes.

4. 4

   Add the greens and cook until wilted.

5. 5

   Season the eggs with salt and pepper and whisk in the remaining 2 tablespoons of oil.

6. 6

   Pour the eggs into the skillet and cook over moderate heat until the bottom and sides begin to set.

7. 7

   Lift the sides of the frittata to allow the uncooked eggs to seep under.

8. 8

   Continue cooking until the bottom is set and the top is still runny, 3 minutes.

9. 9

   Sprinkle the Parmigiano-Reggiano on top.

10. 10

    Transfer the skillet to the oven and bake for about 8 minutes, until the center of the frittata is set.

11. 11

    Slide the frittata onto a cutting board.

12. 12

    Cut into 1 1/2-inch squares and serve hot, warm or at room temperature.

* Per serving · 4 servings · Values may vary.