Savory Caramelized Onion Frittata

Name: Savory Caramelized Onion Frittata
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Yield: 4 servings
Ingredients: 6 large eggs; 2 medium onions, sliced; 2 tablespoons olive oil; 1/2 cup milk; Salt and pepper to taste; Fresh thyme for garnish

Highlighted under: Homestyle Comfort Plates

I absolutely adore making frittatas, and this Savory Caramelized Onion Frittata is one of my favorites! The sweet richness of the caramelized onions combined with fluffy eggs creates a delightful meal that’s perfect for breakfast, brunch, or even a light dinner. The best part is how simple it is to whip up, making it an ideal choice for those busy mornings when I want something comforting yet impressive. Once you try it, you'll understand why it’s become a staple in our home.

Created by

Olivia

Last updated on 2026-01-08T12:58:31.736Z

When I first tried caramelizing onions, I was amazed at how their sweetness transforms their flavor entirely. It’s a game changer in many dishes, especially frittatas. I learned that cooking them slowly over low heat allows the natural sugars to develop, leading to a depth of flavor that perfectly complements the eggs. A little patience goes a long way!

I also discovered that adding a hint of fresh herbs like thyme elevates the dish further, adding a fragrant note that pairs beautifully with the onions. It’s such a versatile dish, making it an excellent canvas for whatever ingredients I have on hand.

        Why You'll Love This Recipe
        The perfect balance of sweet and savory flavors
Easy to customize with your favorite veggies or cheeses
Great for meal prep, leftovers save wonderfully

      

The Art of Caramelizing Onions

Caramelizing onions transforms their sharpness into a sweet, rich flavor that elevates this frittata. It's essential to cook them over medium-low heat; rushing the process can lead to burnt pieces rather than that beautiful golden hue. Keep an eye on them and stir every few minutes to ensure they cook evenly. After about 15-20 minutes, the onions should be soft and sticky, with a deep caramel color.

For an extra layer of depth in flavor, you can add a splash of balsamic vinegar or a pinch of sugar when the onions are nearly done. This will enhance their sweetness and provide a nice contrast to the savory eggs. Just be careful not to overpower the dish—balanced sweetness is key for the perfect frittata.

Egg Mixture Mastery

The egg mixture is where you have the chance to customize your frittata. Using a combination of eggs and milk makes the frittata fluffy and creamy. If you're aiming for a lighter version, consider replacing some of the milk with water or using egg whites instead of whole eggs. However, be cautious with liquid ratios; too much will result in a soggy frittata.

Be sure to season your egg mixture well before pouring it over the caramelized onions. A good pinch of salt enhances the overall flavor and helps the frittata rise. If you enjoy cheese, adding a handful of shredded cheese to the egg mixture can add richness and enhance the overall creaminess. Just remember to factor in any extra salt the cheese may carry.

Ingredients

For the Frittata

6 large eggs
2 medium onions, sliced
2 tablespoons olive oil
1/2 cup milk
Salt and pepper to taste
Fresh thyme for garnish

Preparation Steps

Caramelize the Onions

In a large skillet over medium-low heat, add olive oil and sliced onions. Cook slowly, stirring occasionally, for about 15-20 minutes until the onions are golden brown and caramelized. Season with salt and pepper.

Mix the Eggs

In a bowl, whisk together the eggs and milk until well combined. Season with salt and pepper to your liking.

Combine and Cook

Preheat the oven to 375°F (190°C). Once the onions are caramelized, pour the egg mixture over them in the skillet. Cook for 5 minutes on the stovetop, then transfer to the oven and bake for an additional 15 minutes, or until the eggs are set.

Serve

Once the frittata is done, let it cool for a few minutes before garnishing with fresh thyme. Cut into wedges and enjoy warm or at room temperature.

Pro Tips

Feel free to add in other ingredients like spinach, bell peppers, or cheese to customize your frittata and make it even more delicious!

Storage and Reheating

This Savory Caramelized Onion Frittata is perfect for meal prep! After it cools, store leftovers in an airtight container in the fridge for up to 4 days. When ready to eat, reheat individual slices in a skillet over medium heat for about 5-7 minutes, or pop them in the microwave for 30-60 seconds. Either method will bring back the fluffy texture of the frittata.

If you want to freeze your frittata, make sure to first cut it into wedges and wrap them tightly in plastic wrap, followed by aluminum foil. It can be frozen for up to 3 months. When you're ready to enjoy it, thaw it overnight in the fridge and reheat as mentioned above.

Flavor Variations

While caramelized onions provide a foundational flavor, don't hesitate to explore other tasty additions. Consider incorporating sautéed spinach, bell peppers, or mushrooms for a heartier frittata. These ingredients not only add nutritional value but also contribute delightful textures that contrast beautifully with the softness of the eggs.

Herbs and spices can also be used to infuse your frittata with personality. Besides fresh thyme for garnish, a sprinkle of smoked paprika or a dash of chili flakes can add an exciting kick. Experimenting with different cheeses like feta, goat cheese, or even a sharp cheddar can also take your frittata experience to a whole new level.

Questions About Recipes

→ Can I make this frittata ahead of time?

Yes, this frittata stores well in the refrigerator for up to 3 days, making it great for meal prep.

→ How do I know when the frittata is cooked?

The frittata is done when the edges are set, and the center is slightly puffed and no longer jiggly.

→ Can I freeze the frittata?

Yes, you can freeze leftovers. Just cut it into slices and wrap them tightly. Thaw in the refrigerator before reheating.

→ What can I serve with this frittata?

This frittata pairs wonderfully with a simple green salad or crusty bread for a complete meal.