Cheesy Mushroom Frittata

updated Oct 8, 2021
Cheesy Mushroom Frittata Recipe

This tender egg breakfast bake is packed with seared mushrooms, nutty Gruyère cheese, and lots of fresh herbs.

Serves4 to 6

Prep15 minutes

Cook18 minutes to 22 minutes

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My appetite for one-skillet dinners knows no limit, and frittatas are the ultimate incarnation. They rely on ingredients like eggs, cheese, and dairy that I always have on hand, and are only made better when fresh veggies and herbs are added.

In the version I’m sharing here, a mixture of fresh mushrooms are browned in butter and dressed up with fresh thyme, while a secret spoonful of Dijon mustard amplifies its savory flavor. Don’t forget the nutty Gruyère cheese, which melts like a dream into the fluffy egg bake. Here’s how to do it.

What’s the Difference Between a Frittata and a Quiche?

A trio of factors come into play when determining whether an egg dish is a frittata or a quiche.

  1. Presence of a crust: Frittatas are crustless, while quiche are built on a pastry.
  2. Baking vessel: Frittatas are prepared in a skillet (usually well-seasoned cast iron or nonstick) because they start on the stovetop and finish in the oven. Quiche are baked in a pie pan to support the custard and crust.
  3. Egg-to-dairy ratio. Frittatas consist mainly of eggs with a splash of dairy to maintain moisture. Quiche can handle more dairy because they have the support of the crust.

What Are the Best Mushrooms for Frittatas?

The more mushrooms the merrier, and there’s no wrong way to mix ’em. I like to start with cremini (also known as baby portobello), which have a little more depth and interest than white button. From there, I look for shiitake, oyster, or other wild mushrooms to add variety in texture and flavor.

Can You Meal Prep Frittatas?

Yes! When you start with the right proportion of eggs to dairy and cook the eggs until they’re just done, your frittata will stay tender and appetizing for days. In fact, frittatas are one of those rare foods that are often just as good as leftovers, as they are hot from the oven. To meal prep frittatas, cook as instructed, but skip the broiling step. Slice into servings, then refrigerate in an airtight container to enjoy all week long.

How Should I Serve This Mushroom Frittata?

Frittatas can be served chilled or at room temperature. I often serve slices alongside salad, but I also like to warm a slice and layer it between slices of bread with a swoosh of Dijon, mayonnaise, and baby spinach. You can also cut the frittata into long, thin rectangles and wrap in a tortilla with pickled jalapeños and sliced radishes for quick breakfast burrito.

Cheesy Mushroom Frittata Recipe

This tender egg breakfast bake is packed with seared mushrooms, nutty Gruyère cheese, and lots of fresh herbs.

Prep time 15 minutes

Cook time 18 minutes to 22 minutes

Serves 4 to 6

Nutritional Info


  • 2 ounces

    Gruyère, fontina, or low-moisture mozzarella cheese, shredded (1/2 cup)

  • 8 ounces

    fresh mushrooms, such as white button, cremini, shiitake, or oyster mushrooms, or a combination

  • 2

    medium scallions

  • 1 small bunch

    fresh thyme

  • 8

    large eggs

  • 1/2 cup

    heavy cream, half-and-half, or whole milk

  • 1 teaspoon

    Dijon mustard

  • 1 teaspoon

    kosher salt, divided

  • 1/4 teaspoon

    freshly ground black pepper

  • 2 tablespoons

    unsalted butter, divided


  1. Arrange a rack in the top third of the oven and heat the oven to 400°F.

  2. Grate 2 ounces cheese on the large holes of a box grater (1/2 cup). Remove the stems from 8 ounces mushrooms and discard (or reserve for making stock). Thinly slice the mushrooms. Thinly slice 2 medium scallions, keeping the white and green parts separate. Strip the leaves from 1 small bunch fresh thyme and coarsely chop until you have 1 tablespoon.

  3. Place 8 large eggs, 1/2 cup heavy cream, 1 teaspoon Dijon mustard, 1/2 teaspoon of the kosher salt, and 1/4 teaspoon black pepper in a medium bowl and whisk to combine.

  4. Melt 1 tablespoon of the unsalted butter in a 10-inch cast iron or oven- and broiler-safe nonstick skillet over medium-high heat. Add the mushrooms and remaining 1/2 teaspoon kosher salt, spread into an even layer, and cook undisturbed for 2 minutes. Toss and continue to cook until golden-brown and some of their liquid is released, tossing every 2 minutes, for 4 to 6 minutes more. Add the scallion whites, thyme, and remaining 1 tablespoon unsalted butter. Cook, stirring occasionally, until the scallions soften and begin to brown and the mixture is fragrant, about 2 minutes.

  5. Spread the mushrooms into an even layer. Sprinkle with the cheese, then pour the egg mixture over the vegetables and cheese. Tilt the pan to make sure the eggs settle evenly over the mushrooms. Scatter the scallion greens evenly over the top. Cook undisturbed until the eggs at the edges of the pan begin to set, 1 to 2 minutes.

  6. Transfer the pan to the oven and bake until the eggs are set, 8 to 10 minutes. Check doneness by cutting a small slit in the center of the frittata. If raw egg runs into the cut, continue to bake for another few minutes. If the eggs are set, remove the frittata from the oven. If desired, turn the oven to broil and broil until the top is browned and crispy, 1 to 2 minutes.

  7. Place the pan on a wire rack and let cool for 5 minutes. Loosen the sides of the frittata with a spatula, then slide the frittata out of the pan, if desired. Slice into wedges and serve.

Recipe Notes

Storage: Refrigerate leftovers in an airtight container for up to 4 days.