Cast Iron

Baked Onion-Walnut Frittata

June 23, 2014
3 Ratings
Photo by James Ransom
  • Serves 4 to 6
Author Notes

Very lightly adapted from Martha Rose Shulman's The Simple Art of Vegetarian Cooking. It's a perfect, dead-simple brunch dish, not least because once you put it in the oven, you can tend to everything else that has to be done. I've included Shulman's melted onions recipe here, but feel free to substitute your own version of caramelized onions. (Or your own filling period. The template for the baked frittata is what's most important here.) And finally, if you don't have Greek yogurt, I've strained regular yogurt for just an hour or so before baking this. It's worked plenty well enough. —Nicholas Day

What You'll Need
  • Melted Onions
  • 1 pound onions, either chopped or thinly sliced
  • 2 tablespoons olive oil
  • 1 teaspoon fresh thyme leaves
  • 1 garlic clove, minced
  • Frittata
  • 2 tablespoons olive oil
  • 6 eggs, large
  • 1/2 cup Greek yogurt
  • 1/3 cup walnuts, finely chopped
  • 1/4 cup fresh parsley, finely chopped
  1. Melted Onions
  2. In a large skillet, warm the olive oil over medium heat and then add the onions and cook, stirring, until they soften, about five minutes or so. Then add 1/2 teaspoon sea salt, the thyme and the minced garlic. Turn the heat to low and cover. Cook, stirring frequently, for another 30 to 40 minutes, or until the onions are very soft and lightly colored but not browned.
  1. Frittata
  2. Preheat the oven to 350 degrees F.
  3. Add the olive oil to a large skillet, ideally cast iron, brushing the sides with the oil. Then place the pan in the hot oven for five minutes.
  4. While the pan is heating up, whisk the eggs in a large bowl. Season with salt and pepper and whisk in the yogurt. Then stir in the melted onions (above), the walnuts and the parsley.
  5. Remove the skillet from the oven and pour in the egg mixture. It should sizzle. Return the skillet to the oven and bake until puffed and lightly colored, about 30 minutes. Serve hot, warm, or at room temperature.

See what other Food52ers are saying.

  • Neil Feder
    Neil Feder
  • krikri
  • MisoForBreakfast
  • AntoniaJames
I'm the author of a book on the science and history of infancy, Baby Meets World. My website is; I tweet over at @nicksday. And if you need any good playdoh recipes, just ask.

9 Reviews

Neil F. December 1, 2018
Sorry but this recipe was a disaster for me. After all that cooking and baking, I was left with a wet spongy brown colored mess. Will never make again
krikri November 21, 2015
I confess I only used this recipe as a springboard, but if my result was anything like the intended result, this is fabulous. I used large quantities of whatever we had in the fridge, including spinach and the recommended walnuts. We had fewer eggs than I expected (three!) but no matter. It all went in and it was delicious.
MisoForBreakfast April 5, 2015
I made this for Easter brunch and it was amazing! The melted onions were absolutely delicious, and I added a bit of fresh thyme to the egg mixture so that I could get the depth of the cooked thyme in the onions but still retain some of that fresh herbal flavor in the dish. Everyone loved it.
Katie D. April 3, 2015
this may be a silly question, but is a 12 inch skillet too big for this recipe?
macfadden April 1, 2015
This was very tasty, though with caramelizing the onions and baking the frittata it is a weekend dinner for me. Like another commenter, I was worried about cooking the garlic for that long, but it turned out fine, and the thyme didn't suffer from half an hour of cooking, either.
dafefe July 20, 2014
A few modest pointers; first the melted onions can be prepared in less time, the trick is adding small amount of warm broth to the mixture, and only enough time, to let the broth and vegetables cook together, with excess moisture boiled away (5to 7 minutes), adding the herbs last minute(cooking fresh basil or thyme for 40 minutes is a heresy); second, you may heat the frying pan for Frittata, on medium heat, by itself. And add the cold oil to hot pan and then the egg, onion mixture which later can be placed in preheated 350 degree oven, with cover on. The whole, idea of Frittata is a quick egg dish.
Now, the truth is baba, used to slow bake the egg Frittata, in a 250 degree oven, for an hour. Her ingredients were all mixed fresh, without pre cooking, and poured into hot pan, and hour long slow baking. By my own admission the flavors were well amalgamated. But then it was 1950s. Things change.
AntoniaJames October 23, 2014
Thank you, dafefe for the tips. ;o)
Chickenfog July 6, 2014
Hmmm, curious if anyone actually made this exactly as written. Cooking minced garlic for 40 minutes? How does it not burn no matter how low you set the heat?
VA T. July 9, 2014
the moisture from the 'melting onions' keeps the garlic sufficiently hydrated. have done this several times.