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Mushroom, Caramelized Onion and Feta Frittata on a plate with brussels sprouts.

Once you get into a frittata groove, it’s hard to get out. And that’s not a bad thing.

A frittata is an Italian omelet, but one in which all of the add-ins (cheese, veggies, meat, rice, what have you) are beaten directly into the eggs. It’s like a cousin to a quiche but more egg-based (usually no milk or cream added) and no crust. So, also a bit easier and less involved.

Mushroom, Caramelized Onion and Feta Frittata in a pan.

This Mushroom, Caramelized Onion, and Feta Frittata was born of some extra noodles from a chicken noodle soup which gives the frittata some body and chew, mushrooms I forgot to use in a stew, and other miscellaneous staples. Use ANY kind of mushrooms you like, they all work. Oh, and eggs, of course. This is earthy and deep, and simple in flavor.

Leftover frittata makes an extremely happy lunch, I think.

This Mushroom, Caramelized Onion and Feta Frittata makes a perfect vegetarian light lunch or dinner. This is earthy and deep and simple in flavor.

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Plated slice of Mushroom, Caramelized Onion and Feta Frittata next to the rest of the frittata.

And then….keep going! Make up your own and change them up all day long, or try one of these other recipes.

More Frittata Recipes

I can stop any time I want.

Mushroom, Caramelized Onion and Feta Frittata in a pan and on a plate.

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Mushroom, Caramelized Onion and Feta Frittata

5 from 2 votes
Prep: 10 minutes
Cook: 30 minutes
Total: 40 minutes
Servings: 6 People
With a dozen eggs in the fridge, a frittata is never far away.


  • 1 tablespoons olive oil
  • 2 onions thinly sliced
  • Kosher salt and freshly ground pepper to taste
  • 1 tablespoons butter
  • 3 cups sliced mushrooms
  • 1 ½ cups cooked egg noodles or other cooked pasta
  • 1 teaspoon fresh minced thyme or 1/2 teaspoon dried
  • 10 large eggs
  • 1 cups crumbled feta cheese


  • Preheat the broiler, with the rack set about 4 inches from the heat source.
  • In a medium (10-inch) broiler-proof skillet, preferably cast iron, heat the oil  over medium heat. Add the onion, season with salt and pepper, and cook, stirring occasionally until the onions are nicely browned and quite soft, about 10 minutes.  Remove the onions to a plate.
  • Melt the butter in the same skillet and add the mushrooms, seasoning with salt and pepper.  Turn the heat to medium high and sauté for about 8 minutes, until there is no liquid left in the pan and the mushrooms are beginning to brown.
  • Meanwhile, in a medium bowl, whisk the eggs, and season with salt and pepper.  Return the onions to the pan and add the noodles and thyme.  Stir to combine, pour in the eggs, and stir to blend everything evenly.  Lower the heat to medium-low and with a spatula, gently lift the edges of the frittata so that the uncooked eggs have the chance to run underneath the noodle-vegetable mixture.  Do this every couple of minutes until the frittata is pretty set on the bottom, but the top and middle are still a bit runny.
  • Sprinkle the feta cheese on top of the frittata and place the skillet under the broiler.  Broil until the frittata is set, and the cheese is melted and the whole top is lightly golden, 2 to 4 minutes. Remove from the oven and let sit for a minute or two, then serve in wedges.  DON’T FORGET THAT THE HANDLE OF THE PAN IS HOT!  You can leave a dishtowel draped over it to remind yourself.  Again, also great at room temp or even cold.


Frittata is delicious leftover, whether hot or cold!


Calories: 288.99kcal, Carbohydrates: 16.69g, Protein: 16.5g, Fat: 17.55g, Saturated Fat: 7.76g, Cholesterol: 311.67mg, Sodium: 405.74mg, Potassium: 338.07mg, Fiber: 1.63g, Sugar: 3.96g, Vitamin A: 584.05IU, Vitamin C: 4.25mg, Calcium: 177.55mg, Iron: 2.06mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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  1. Am I overlooking something? In #4 of the instructions, you mention potato-egg mixture. Where did the potatoes come from? How many? Sliced, cubed, shredded? I appreciate any clarification you can give, as I would like to try this recipe.

  2. I made this frittata yesterday evening and it was heavenly delicious!! I didn’t have any pasta but I did have some thinly sliced, smothered potatoes from the day before, so I used 1 & 1/2 cups of those instead of egg noodles. I don’t care for feta cheese, so in its place, I used shredded provolone. Oh my goodness, it was SO good!! Thanks for sharing your recipe!

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