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Caramelized Onion Frittata

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.

slice of caramelized onion frittata on a wood spatula

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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!

Caramelized Onion Frittata

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


  • 8 large eggs
  • 1/3 cup heavy cream
  • 1 tsp sea salt
  • 1/2 tsp freshly ground black pepper
  • 1/4 cup chopped fresh chives
  • 6 oz feta, crumbled, divided
  • 2 Tbsp extra-virgin olive oil
  • 1 cup caramelized onions
  • 4 cups baby kale (5oz)


  1. Preheat the oven to 400°F with a rack in the center position. In a large bowl beat the eggs. Add the cream, salt, pepper, chives and 2/3 of the feta cheese, mix to combine.

  2. In a 10-inch oven-safe skillet, heat the olive oil over medium, until glistening. Add the kale to the oil and cook until wilted, about 2 minutes. Add in the caramelized onions, breaking them up until they are mixed in with the kale. While still over medium heat, carefully pour in the egg mixture and let the edges set, undisturbed, for 2 minutes.

  3. Place the skillet in the oven on the center rack until the eggs have completely set and are no longer jiggly in the center, about 10 minutes. Sprinkle with remaining feta.

  4. 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 Schmidt

    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.

  • 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 McGovern

    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 Koses

    This recipe was DELICIOUS and a repeat!