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Caramelized Onion Frittata

June 11, 2024

A silky pour of heavy cream helps this vegetable-laden frittata stay tender, light and bouncy, even as we load it up with rich caramelized onions, tangy feta and a veritable garden of baby kale.


caramelized onion frittata in a blue cast iron skillet topped with baby kale, feta and caramelized onions

A Whole Lotta Frittata

Thie easy breakfast frittata is rich with cream and caramelized onions—DIY, friends! They’re SO easy— and yet it still manages to get the “healthy-ish” stamp of approval, since our vegetable frittata recipe is packed with more baby kale than it is cheese and cream. Plus, with no crust (btw, crust vs. no crust is the difference between a quiche and a frittata), our frittata recipe is as low-carb as they come. Learning How To Make A Frittata is simple, you’ve got this!

slice of caramelized onion frittata on a wood spatula

What Is a Frittata?

Eggs + whatever you’ve got + oven= frittata. The Italian answer to a classic French omelette, a frittata is essentially a crustless quiche, and while they make a wonderful breakfast, they’re great for dinner, too. At its core, a frittata is really just a thrifty, easy way to use up leftovers—take whatever bits and pieces you’ve got lurking around your fridge, toss them in a big (oven-safe) skillet with some whisked eggs, bake and call it brunch (or breakfast, or dinner). Classic Neapolitan pasta frittata is a great (and oh-so-Italian) example of this, but our recipe keeps things a little healthier than that—no pasta, here.

blue cast iron skillet with sautéed baby kale
blue cast iron skillet with sautéed baby kale and caramelized onions
blue cast iron skillet with caramelized onions and baby kale with beaten eggs being poured over the top
caramelized onion and kale frittata baked in a blue cast iron skillet

How To Make a Frittata:

Frittata is a forgiving dish, and our recipe is no exception. Think of our frittata recipe as a template to which you certainly do not have to stick closely. Maybe make it our way the first time, so you know how a frittata works. Once you’ve mastered our basic baked frittata recipe, feel free to change it up! Here’s what to do:

  1. Give eight eggs a really good whisk.
  2. Add cheese (we love feta for this) a pinch of salt, pepper and heavy cream to the eggs. The heavy cream is a “nice to have”, not a must. If you don’t have it, skip it! Your frittata will still be delicious.
  3. Sauté the baby kale in olive oil (not extra virgin). You could also use regular kale here—just remove the tough stems and slice it into ribbons.
  4. When the kale is wilted, and the pan is coated with a good slick of olive oil, add the caramelized onions and the whisked eggs and dairy to the pan.
  5. Let the frittata begin to set a bit, and then move it to the oven to finish.
  6. When it’s puffy and just-set in the middle, it’s done!
caramelized onion frittata in a blue cast iron skillet with one slice removed

What To Serve with Frittata

We love to serve this with a simply-dressed green salad as a healthy, elegant brunch. Whatever your favorite breakfast potatoes are—crispy roasted potatoes, for example—would also be a great frittata side dish. Just don’t forget the coffee and mimosas!

Tools You’ll Need to Make a Frittata:

wooden plate with a slice of caramelized onion frittata served with a fresh arugula salad

Other Any-Time-of-Day Egg Recipes:

We go through eggs by the two-and-three dozen—how about you? Healthy, high in protein, quick to cook and so versatile, they’re just the best. Here are three recipes we whisk up on the regular:

How’d It Go Over?

We’d love to know! Snap a photo of your caramelized onion, feta and baby kale frittata, and maybe even a video of the beautiful people you feed it to. Tag us on Instagram using @themodernproper and #themodernproper. Happy eating!

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Caramelized Onion Frittata

  • Serves: 8
  • Prep Time:  10 min
  • Cook Time:  1 hr 5 min
  • Calories: 228


  • 8 large eggs, beaten
  • ⅓ cup heavy cream
  • 1 teaspoon sea salt
  • ½ teaspoon freshly cracked black pepper
  • ¼ cup chopped fresh chives
  • 6 ounces feta cheese, crumbled
  • 2 tablespoons extra-virgin olive oil
  • 4 cups baby kale (about 5 ounces)
  • 1 cup caramelized onions


  1. Preheat the oven to 400°F with a rack in the center position.

  2. In a large bowl, combine the eggs, cream, salt, pepper, chives, and two-thirds of the feta.

  3. Heat the olive oil in a medium ovenproof skillet over medium heat. Once the oil is glistening, add the kale and cook, stirring, until wilted, about 2 minutes. Stir in the caramelized onions until well incorporated. Carefully pour in the egg mixture and cook, undisturbed, until the edges are just set, about 2 minutes.

  4. Transfer the skillet to the oven and bake until the eggs are completely set, about 10 minutes. The eggs shouldn’t move when you jiggle the pan.

  5. Top the frittata with the remaining feta. Slice into 8 wedges and serve.

Nutrition Info

  • Per Serving
  • Amount
  • Calories228
  • Protein10 g
  • Carbohydrates7 g
  • Total Fat18 g
  • Dietary Fiber1 g
  • Cholesterol218 mg
  • sodium714 mg
  • Total Sugars3 g

Caramelized Onion Frittata

Questions & Reviews

Join the discussion below.

  • Jordan

    If I wanted to convert this to a quiche would you adjust anything or is at easy as pouring the egg mixture into a crust instead of a skillet?

    We imagine it would work ok. We also have a recipe for Tomato, Basil & Caramelized Onion Quiche on our site as well. Either way, hope you enjoy.

  • Kim

    This recipe is soooo easy and sooooo delicious! Love it!

    Thanks Kim, so glad you loved it!

  • Haley

    Delicious and I love the egg to veggie ratio. That said, only giving this 4 starts because it was SO SALTY, and I like really salty! I will use half (or less) of the salt next time. I should have known as I had this same problem with the frittata in your cookbook (one of my fav cookbooks!).

    Thanks Haley, glad you enjoyed it. Sorry to hear it was too salty for you but sounds like you know how to fix it to your liking next time.

  • Olivia

    Delicious! It was a little salty for me, but it could just be taste.

    Glad you enjoyed it Olivia!

  • Megan

    Such a great recipe! We make it almost weekly!

    Thanks Megan, that is so great to hear!! Glad you love it so much!

  • Rebecca

    This recipe was DELICIOUS and a repeat!