146 calories; 11.1 g fat; 2.5 g saturated fat; 248 mg cholesterol; 99.7 mg sodium; 2.3 g carbohydrate; 0.5 g fiber; 1.1 g sugar; 9 g protein
Preheat oven to 350°F.
Heat 1 tablespoon of oil over medium heat in a 9–10 inch oven-safe skillet*. Add onion and sautéuntil translucent, about 5 minutes. Add spinach and mushrooms. Sautéuntil spinach has wilted and mushrooms are tender.
Add remaining oil to the skillet. Add eggs and season with salt and pepper, as desired. Reduce heat to low and cook until the frittata is slightly set, about 3 minutes.
Place skillet in the oven. Bake for 10–15 minutes or until frittata is lightly browned and puffy. Slice and serve.
*if you do not have an oven-safe skillet, you can sauté vegetables on the stove, then transfer to a baking dish. Add eggs and bake for 12-18 minutes.