Chicken, Spinach, and Mushroom Frittata

1 . Stage

Set an oven rack about 6 inches from the heat source and preheat the oven's broiler.

2 . Stage

Heat 1 tablespoon oil in a large, nonstick, oven-proof skillet over medium heat. Add mushrooms and green onions; cook and stir until softened, about 1 minute. Transfer to a large bowl.

3 . Stage

Add egg whites, eggs, and spinach to the mushroom mixture; stir with a fork until well combined.

4 . Stage

Heat remaining oil in the same skillet over medium heat. Pour in egg mixture and scatter cooked chicken over top. Cover the skillet and cook until eggs are set around the edges, about 4 minutes.

5 . Stage

Remove the cover and transfer the skillet to the oven. Broil until lightly browned and the center is set, about 4 minutes.

6 . Stage

Remove from the oven, top with mozzarella cheese, and cover; let stand until cheese is melted, about 1 minute. Cut into 4 slices and serve.