This past weekend was weird. It was above zero degrees Celsius (that’s around 39 degrees F, if you’re wondering) and it didn’t snow, which meant I got to do my long run outside on regular, non-icy pavement on Sunday. I took off my gloves and ran as if it were late fall. Pretty amazing, really.

Caramelized Onion, Kale and Feta Frittata

When I’m not stuck on a treadmill and taking the bus to and from the gym, this gives me time to get up early and go for my run before P gets up. We rarely get the chance to eat breakfast together while I’m training in the winter, and spend many mornings waving a quick “hello” and “goodbye” while shoving muffins into our mouths and running out the door. On these rare mornings that we do get to spend time together, I like making either eggs or some sort of maple syrup covered treat. Something that doesn’t take too long to make and something that we can sit down and enjoy together.

This past weekend I went with eggs. And I am so pleased that I did.

Caramelized Onion, Kale and Feta Frittata

Frittatas are great because they can be made for breakfast or dinner and leftovers can easily be stored in the fridge for a few days before being reheated. I decided to go with a combination of caramelized onions, kale and feta for this recipe for a couple of reasons:

1. Caramelized onions are the best and should be added to as many savoury recipes as possible.
2. Kale is in season right now. And so are onions.
3. Feta is amazing. And is made even better when paired with caramelized onions.

Caramelized Onion, Kale and Feta Frittata

So grab a fork and dig in! I sure am..

Caramelized Onion, Kale and Feta Frittata

Prep Time: 20 minutes

Cook Time: 50 minutes

Total Time: 1 hour, 10 minutes

Yield: 4-6 servings


  • 2 tbsp extra virgin olive oil
  • 3 onions, finely sliced
  • 1 tbsp red wine vinegar
  • 1 tsp granulated sugar
  • 1 tsp Worcester sauce*
  • 1/4 tsp dried thyme
  • Pinch of salt and pepper, to taste
  • 2 garlic cloves, minced
  • 2 big handfuls (3-4 cups) chopped kale, ribs removed
  • 6 large eggs
  • 1/4 cup plus 2 tbsp milk
  • 1/3 cup crumbled feta cheese
  • Hot sauce, for serving (optional)


  1. Preheat oven to 350 degrees F.
  2. Over medium-low heat, add olive oil into a 10" cast iron skillet. Add the sliced onions and stir to coat in oil. Cook onions for about 20 minutes, checking every 5 to 10 minutes - stirring and scraping the brown bits on the bottom of the skillet. Add vinegar, sugar, Worcester and dried thyme and continue to cook for a further 5 minutes, stirring often until reduced and the onions look glossy. Add minced garlic and chopped kale. Stir and let cook for an additional 2-3 minutes until the kale wilts. Season with salt and pepper.
  3. In a medium bowl, whisk together the eggs and milk. Add some salt and pepper to taste and, over low heat, add egg mixture to the onions and kale and cook for 3 minutes, stirring only once at the beginning to evenly disperse ingredients.
  4. Crumble the feta over top of the egg mixture and transfer the skillet to the preheated oven. Cook until middle is set solid, about 20 minutes.
  5. Let rest for 5 minutes, slice and enjoy warm. I like to add a few shakes of hot sauce on mine!
  6. Leftovers can be refrigerated and reheated the next day.


Recipe inspired by My Darling Lemon Thyme

To keep this vegetarian, be sure to use vegan Worcester sauce.

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14 Responses to Caramelized Onion, Kale and Feta Frittata

  1. Such a gorgeous trio of ingredients- you can’t go wrong! Winter training is the pits… so great you got your long run outside sans gloves though!

  2. Sues says:

    It was 64 degrees here in Boston yesterday, which is just wrong! But I do know I thoroughly enjoyed it 🙂

    This frittata has all of my favorite things involved!

  3. I love love love caramelised onions so a way to incorporate them into my breakfast is great.

  4. Sugar et al. says:

    This is amazing! Caramelised onion with feta is a lovely combination. I’d love to make this on the weekend.

  5. The feta looks incredible! I love the kale in there, too 🙂 Brunch inspiration for sure, pinning!

  6. Fabulous frittata Katrina. I love feta in frittatas for the wonderful salty element. And so nice with the onions and kale, I’m sure!

  7. Kankana says:

    Tangy feta with sweet caramelized onion! Lovely combination. All one needs is some crunchy bread and a cup of tea 🙂

  8. Now that is what I call a frittata! This looks and sounds amazing, definitely a perfect treat when you spend the morning with a loved one 🙂 x

  9. Joanne says:

    Yay for warm weather and outdoor runs! I don’t know how you do training runs on a treadmill…you have away more determination than I ever will…but I bet knowing that you have this frittata waiting at home is incentive to get through anything.

  10. Now this is my kind of frittata!

  11. Sabrina says:

    Yum, this looks great! And those caramelized onions sound amazing!

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