Mushroom Frittata Recipe

5 from 1 vote

This mushroom frittata is an easy vegetarian breakfast made with fluffy eggs, sautéed mushrooms, spinach, and melty Gruyère. It’s simple to prep, crowd-friendly, and perfect for brunch or make-ahead mornings.

Prep Time5

Cook Time30

Total Time35

Course: Breakfast, brunch

Cuisine: American

Servings: slices

Calories: 227kcal

Author: Becky Hardin

Equipment

Cast Iron Skillet

Ingredients

12 large eggs 1 carton
½ cup milk
1 teaspoon kosher salt divided
¼ teaspoon ground black pepper
2 tablespoons olive oil divided
1 shallot finely chopped
2 cloves garlic minced
2 sprigs fresh thyme
8 ounces cremini mushrooms sliced*
2 cups fresh spinach **
1 cup shredded Gruyère cheese ***
grated Parmesan cheese optional, for topping

Instructions

Preheat oven to 425°F. Whisk the eggs, milk, ½ teaspoon salt, and pepper in a large bowl.
12 large eggs, ½ cup milk, 1 teaspoon kosher salt, ¼ teaspoon ground black pepper
Heat 1 tablespoon of oil in a large oven-safe skillet over medium heat. Add in the shallot and ¼ teaspoon salt, and sauté until softened, about 3-4 minutes.
2 tablespoons olive oil, 1 shallot
Stir in the garlic and thyme leaves and cook until fragrant, about 1 minute.
2 cloves garlic, 2 sprigs fresh thyme
Add in the mushrooms and ¼ teaspoon salt, and cook until softened and the excess liquid has been evaporated, about 3-5 minutes.
8 ounces cremini mushrooms
Stir in the spinach and cook until wilted, about 3 minutes.
2 cups fresh spinach
Transfer the mushroom mixture to a plate or bowl.
Heat another tablespoon of oil in the skillet and swirl it around until it covers the bottom of the pan.
Pour the egg mixture into the pan. Add the mushroom and spinach mixture in an even layer over the eggs, and sprinkle Gruyère cheese over top.
1 cup shredded Gruyère cheese
Transfer the skillet to the oven, and bake for 15 minutes, until the eggs have just set. Top with additional fresh thyme and grated Parmesan cheese, if desired.
grated Parmesan cheese

Notes

*Feel free to use your favorite variety of mushrooms.

**If using frozen spinach, be sure to thaw it fully and wring out excess moisture before using.

***You can use Swiss, white cheddar, Fontina, or Gouda cheese in place of Gruyere.

Tips:

I recommend using a cast-iron skillet for the most even cooking.
Whisk the eggs vigorously to incorporate air, which helps make the frittata lighter.
Always cook your veggies in the pan before adding your eggs. Leave everything slightly underdone; it will finish cooking in the oven.
Take care not to burn the shallot or garlic; this could lead to a bitter-tasting frittata.
Mix in caramelized onions, bacon bits, sautéed leeks, asparagus, zucchini, broccoli, or any other veggies you might have in your fridge.
Shred a block of cheese to avoid the added starch in pre-shredded cheese. Finely shredded also melts better without getting a gritty texture.
Don’t stir the eggs once they’re in the pan; let them set gently for a clean frittata texture.
You can gently lift the edges of the frittata while it’s baking so uncooked egg can flow underneath; this helps the center set evenly and stay creamy.
If the top browns too quickly, cover loosely with foil for the remainder of the baking time.
A frittata is finished baking when the edges are lightly browned and firm, but the center is still slightly jiggly. You want the center to remain creamy.
Let the frittata rest for 5 minutes after baking. This helps it set further and makes slicing easier.
To flip your frittata, place a plate face down on top of your skillet, then flip so that the frittata falls nicely onto the plate.
Serve warm, at room temperature, or even cold for meal prep-friendly breakfasts.
To reheat without drying out, cover with foil and warm in a 350°F oven for 10-15 minutes.
Nutritional information does not include optional ingredients.

Individual Egg Cups: Sauté the veggies and stir into the eggs, then pour the mixture into a greased 12-count muffin tin and bake in a 350°F oven for about 20-25 minutes.

Make-Ahead: You can fully assemble this frittata and store it in the refrigerator overnight. Simply pop the frittata into the oven in the morning for an easy, delicious breakfast!

Storage: Store mushroom frittata in an airtight container in the refrigerator for up to 3 days or in the freezer for up to 2 months.

Nutrition