Slice of a frittata featuring mushrooms, peppers, and herbs on a white plate

Mushroom and Pepper Frittata Recipe

By Beth Lipton
Reviewed by Ahna Crum, R.D.N.
March 03, 2023

Frittatas are a delicious and easy way to eat high-quality protein, vegetables, and herbs. Combining an array of veggies is an easy way to get a wider variety of nutrients in your diet—plus, a frittata is a perfect place to use up odds and ends from your vegetable drawer.

For this recipe, we highlight bell peppers—a nutrient-dense part of an anti-inflammatory diet. However, some people are sensitive to nightshades like bell peppers. If you suspect you might have a sensitivity that contributes to flare-ups, talk to your doctor or dietitian about substitutions, or feel free to change up the vegetables and spices as you like.

Serve this frittata to the whole family, or make it for yourself to enjoy over a few days. It’s great right out of the oven, cold, or reheated, and it’s tasty any time of day.

This recipe is: gluten free

Prep time: 20 minutes

Cook time: 40 minutes

Start to finish: 1 hour

Serves 4


  • 10 large eggs
  • ⅓ cup plain unsweetened almond milk (or other milk of choice)
  • 1 tablespoon dried oregano
  • ½ teaspoon freshly ground black pepper
  • 1 teaspoon fine sea salt, divided
  • ½ cup freshly grated Parmesan cheese, divided (optional)
  • 2 tablespoons extra virgin olive oil, divided
  • 1 pound white button or cremini mushrooms, sliced (about 5 cups)
  • 2 medium shallots, chopped (about 1 ½ cups)
  • 2 large bell peppers (we used 1 red and 1 orange), seeded and finely chopped (about 2 ¼ cups)
  • 3 cloves garlic, minced (1 tablespoon)


Preheat the oven to 375 F.

In a large bowl, beat the eggs with the almond milk, oregano, pepper, and ½ teaspoon salt until well combined. Stir in ¼ cup Parmesan, if using.

In a large (10-inch) ovenproof skillet, add 1 tablespoon of the oil and warm it over medium-high heat. Add the mushrooms and season with ¼ teaspoon salt. Stirring occasionally, cook until the mushrooms have begun to brown in spots, about 8 to 10 minutes.

Reduce the heat slightly to just above medium. Add another 1 tablespoon of oil in the skillet with the mushrooms. Add the shallots and peppers. Season with ¼ teaspoon salt and cook, stirring occasionally, until the vegetables are tender and beginning to caramelize, about 7 to 9 minutes. Add the garlic and sauté until fragrant, about 1 minute.

Mushrooms, onions, and peppers cooking in a cast iron skillet

Reduce the heat to medium. Spread the vegetables evenly in the skillet and pour in the egg mixture. Cook without stirring until the edges begin to set, about 3 to 5 minutes. Sprinkle with the remaining ¼ cup Parmesan, if using, and transfer the skillet to the oven.

Egg and herb mixture being poured from a while bowl into a cast iron skillet of veggies

Bake about 12 to 14 minutes, until the frittata is just set in the center—it shouldn’t be wobbly, and a toothpick or paring knife inserted into the center should come out clean.

Cut into wedges and serve. If you have leftovers, let cool and then wrap and refrigerate for up to 3 days.

A single slice of the finished mushroom and pepper frittata, on a white plate


  • Try adding ½ cup crumbled soft goat cheese or feta to this frittata instead of the Parmesan, if you’re not avoiding dairy.
  • This frittata tastes even better the day after it’s made. Enjoy it cold, or rewarm it in a toaster oven.

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