Mushroom and Swiss Cheese Frittata
This light yet satisfying Swiss, Mushroom, and Spinach Frittata blends earthy mushrooms, tender spinach, and rich Emmentaler cheese into a fluffy, golden-baked egg dish. Low in carbs and high in protein, it’s a wholesome choice for any meal of the day.
Equipment
- (1) 12-inch Oven-Safe Skillet (nonstick or cast iron)
- (1) Electric Hand Mixer or Stand Mixer with Whisk Attachment
- 2 Large mixing bowls
- 1 Silicone Spatula
- (1) Cheese Grater
Ingredients
- 1 –2 tablespoons extra-virgin olive oil
- 8 ounces fresh button mushrooms thinly sliced (or substitute with crimini)
- 1 clove garlic finely minced
- 5 cups baby spinach leaves loosely packed
- 10 large eggs whites and yolks separated
- 1 cup half-and-half or whole milk
- 1 ¾ cups shredded Emmentaler cheese divided: 1½ cups for the batter, ¼ cup for topping
- 1 teaspoon kosher salt
- ½ teaspoon ground black pepper
Instructions
- Preheat the Oven: Position the oven rack in the middle or slightly above center. Preheat your oven to 400°F (200°C) so it’s ready for finishing the frittata.
- Sauté the Vegetables: In a large 12-inch oven-safe skillet, heat 1–2 tablespoons of olive oil over medium-high heat, just enough to coat the bottom. Add the sliced mushrooms and sauté for about 3–4 minutes until they release moisture and begin to brown. Lower the heat to medium-low and stir in the minced garlic, cooking for 30–60 seconds until fragrant. Gradually add the baby spinach, stirring in batches as it wilts. Once all the spinach is wilted, remove the skillet from heat and let the mixture cool slightly.
- Whip the Egg Whites: In a clean, dry mixing bowl, use an electric hand mixer or stand mixer with a whisk attachment to beat the egg whites until they form stiff peaks. This step creates the light, airy texture of the frittata.
- Prepare the Egg Yolk Mixture: In a separate bowl, whisk the egg yolks until smooth. Stir in the half-and-half (or milk), 1½ cups of shredded cheese, salt, and pepper. Mix until fully combined.
- Fold and Assemble the Frittata: Gently fold the whipped egg whites into the yolk mixture using a silicone spatula, being careful not to deflate the volume. Once blended, pour the egg mixture into the skillet over the cooked vegetables. Sprinkle the remaining ¼ cup of cheese evenly over the top.
- Bake Until Set and Golden: Transfer the skillet to the preheated oven and bake for 10–13 minutes, or until the frittata is puffed, golden on top, and the center is fully set. Avoid overbaking to keep the texture tender.
- Slice and Serve: Remove from the oven and let it sit for a few minutes before slicing. Cut into wedges and serve warm. Enjoy it solo or paired with a light salad or toast.
Notes
- Cheese Tip: Emmentaler provides a nutty richness and creamy melt that’s perfect for frittatas. If unavailable, substitute with Swiss or Gruyère cheese.
- Whipping the Egg Whites: This technique adds volume and fluffiness without the need for baking powder or flour—ideal for a gluten-free and airy result.
- Meal Prep Friendly: Store leftovers in an airtight container in the fridge for up to 5 days. To reheat, microwave briefly or warm in a low oven.
- Vegetable Variations: Feel free to swap or add vegetables like bell peppers, zucchini, or caramelized onions for seasonal variety.
- Cast Iron vs. Nonstick: A well-seasoned cast iron skillet holds heat well and browns beautifully, but a nonstick pan also works for easy cleanup.
