Ingredients
Method
Step 1: Prep the ingredients
- Chop the spinach, slice the mushrooms, and dice the onion. Mince the garlic and crumble the feta if using. Preheat your oven to 375°F (190°C).
Step 2: Sauté the vegetables
- Heat olive oil in a non-stick oven-safe skillet over medium heat. Add onion and cook for 2–3 minutes until soft. Add mushrooms and cook until browned and tender. Stir in garlic and spinach. Cook until the spinach wilts, about 1–2 minutes.
Step 3: Add the egg whites
- Pour the egg whites evenly over the sautéed vegetables. Season with salt, pepper, and chili flakes if desired. Swirl the pan slightly so everything spreads out evenly. Sprinkle feta on top if using.
Step 4: Bake the frittata
- Transfer the skillet to your preheated oven and bake for 8–10 minutes, until the egg whites are set and the top is slightly golden. If you don’t have an oven-safe pan, cover the skillet with a lid and cook on low until firm.
Step 5: Cool, slice, and serve
- Let the frittata cool for a couple of minutes before slicing. Serve warm or at room temperature.
Notes
- Use a non-stick skillet for the best results — it helps the frittata release easily.
- You can swap feta for goat cheese, mozzarella, or even cheddar.
- Want to make it heartier? Add diced chicken or turkey.
- Keeps well in the fridge for 3–4 days — perfect for meal prep.
- Enjoy it hot, cold, or at room temperature.