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Learn how to easily caramelize onions in the oven with this easy kitchen hack! This recipe produces rich, deeply-flavorful and perfectly caramelized onions that just melt-in-your-mouth! These jammy onions are so versatile and take a dish from ordinary to extraordinary – try them on salads, burgers, pizzas, steak and MORE!

Overhead photo of Oven Caramelized Onions on a parchment paper lined sheet pan with a pale blue linen tucked in the corner of the shot.

Update: This recipe was originally published in February 2019. I’ve updated the post below to include more information caramelizing onions in the oven.

About this kitchen hack for caramelizing onions in the oven

Melt in your mouth tender, savory yet candy-sweet, highly addictive caramelized onions.

Honestly, these oven caramelized onions are so exceptionally delicious I was eating them right off the sheet pan in heaping spoonfuls. (Yes my breath was kicking. No shame.)

However, these caramelized onions are not just legit amazing in the taste department, they are also easier than pie to make. The technique of caramelizing onions in the oven, versus on the stove, significantly cuts down on time and the need for constant stirring!

Basically, these onions have the same big, bold flavor, just without all the effort!

What are caramelized onions?

Caramelization is the cooking process in which sugar browns.

Since onions are naturally sweet, caramelized onions come from the simple process of slowly cooking the natural sugar in onions over an extended period of time until they brake down to a deep brown color and are extremely soft and jam-like in texture.

Caramelizing an onion results in a magically sweet, intense onion flavor.

Overhead photo of sliced yellow onions topped with sprigs of thyme, brown sugar, cloves of garlic, salt and pepper - photo of the first part of step 2 of the Oven Caramelized Onions Recipe.

FAQs: frequently asked questions

What kinds of onions are best for caramelizing?

You can caramelize any type of onion, even in the oven, so feel free to try any variety in this oven caramelized onion recipe!

With that said, here are a few tips on types of onions and caramelization:

  • Yellow Onions – Yellow onions are the most versatile, caramelize the fastest and yield the most flavor.
  • Red Onions – With their beautiful purple color, they make a visually exciting addition to a variety of dishes such as salads and pizzas. Just be careful, because over caramelizing can turn them into an off-putting greenish-brown color.
  • White onions – White onions caramelize similarly to yellow onions, however they will be slightly less complex in flavor.
  • Sweet Onions (such as Vidalia or Walla Walla) – Sweet onions will yield a slightly sweeter flavor, however they tend to lack flavor complexity.

When are onions caramelized?

Caramelized onions definitely require patience! You can tell when caramelized onions are done because they will have a deep, rich golden brown color and be extremely soft to the touch.

What are oven caramelized onions good with?

These caramelized onions are incredibly delicious and so versatile! Sweet onions make a wonderful sweet and savory addition to many dishes. Plus, they make a fantastic base of mouthwatering flavor in dips, soups and casseroles. Let’s face it, everything’s better when caramelized onions are involved!

How to use caramelized onions

  • Dips – Finely chop caramelized onions and add them to your favorite creamy dips! Or, simply use them to quickly make onion dip.
  • Soup – Stir caramelized onions into your soups and stews to add a deep, interesting flavor. I love adding it to apple soups, sausage zitis, and this pasta with ground sausage.
  • Steak – Dress up your steaks by adding a healthy spoonful of onions on top!
  • Chicken – Same as steak, caramelized onions are a delicious way to jazz up chicken.
  • Pasta – Add a small amount to creamy or tomato based pastas for a sweet complement of flavor.
  • Pizza – Drop caramelized onions on top of pizza to add a touch of umami and sweetness.
  • Eggs – Mix caramelized onions into frittatas, use them as a filling for omelettes or use them as a topping for scrambled eggs.
  • Burgers or sandwiches – Add a heaping dollop on top of homemade burgers and sandwiches. Or, finely chop caramelized onions and mix them with mayonnaise to make a homemade sandwich spread.
  • Risottos – Garnish your favorite risotto recipes, like this risotto with butternut squash or risotto scallops, with some easy oven onions for extra buttery richness.
  • Quesadillas – Add a couple tablespoons to your quesadilla filling to make things more interesting.
  • Gnocchi Bakes – Use leftover sweet onions to make this ultra-delicious cheesy baked gnocchi.
Angled photo of olive oil being drizzled over sliced onions topped with thyme, garlic, brown sugar, salt and pepper - photo of the second part of step 2 of the Oven Caramelized Onions Recipe.

How long are caramelized onions good for?

Leftover caramelized onions should be stored in an air-tight container or zip-closure bag in the refrigerator. Properly stored, they will last up to a week in the fridge.

Can I freeze caramelized onions?

Since caramelized onions take a bit of time to make, freezing them to have on hand is a great idea!

Caramelized onions freeze beautifully and will keep in the freezer for up to 3 months.

To freeze caramelized onions, allow them to cool completely after cooking. Transfer them to a zip-closure, freezer safe bag and gently press down and around on the bag to flatten them out. Label the bag and transfer it to the freezer.

How to reheat them?

Frozen caramelized onions do not need to be thawed! You can simply use them in a recipe as is.

Overhead, up-close photo of sliced onions drizzled with olive oil and topped with thyme, brown sugar, garlic, salt and pepper before going in the oven - photo of step 3 of the Oven Caramelized Onions Recipe.

Tips for caramelizing onions in the oven

  1. While yellow onions are my preferred onion to use, you can use whatever variety of onion you prefer – red, sweet or white works as well!
  2. Four whole onions will seem like a lot on the baking sheet, but do not be alarmed. Onions will cook down by a ton (they will shrink to about a 6th of the amount).
  3. The brown sugar is optional. I used 1 ½ tablespoons because I like the extra depth of sweetness it gives the caramelized onions.
  4. I tossed my onions 4 times during baking. Please note, the more you toss the onions, the less likely the edges are to burn and the more evenly they will caramelize.
  5. If you don’t like roasted garlic, feel free to discard the cloves when you discard the thyme sprigs or you can keep them whole, mince or slice them. I removed the cloves, thinly sliced them and then tossed them back in the onions before serving.
Overhead, up-close photo of Oven Caramelized Onions drizzled with Worcestershire sauce - photo of step 4 of the Oven Caramelized Onions Recipe.

With the same delicious flavor and half the effort and mess, these oven caramelized onions are a game changer!!

Until next time, friends – to cooking hacks!

Cheyanne

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More onion recipes!

The best Caramelized Onions – in the oven! (Kitchen hack!)👇

Overhead, up-close photo of Oven Caramelized Onions.

Oven Caramelized Onions Recipe

5 from 10 votes
Total Time: 1 hour 5 minutes
Prep Time: 10 minutes
Cook Time: 55 minutes
Servings: 6
This Oven Caramelized Onions Recipe is an easy, mostly hands off kitchen hack on how to caramelize onions in the oven!  Add mouthwatering flavor and take a dish from ordinary to extraordinary with these perfectly caramelized onions!
(Scroll down for the detailed measurements and instructions in the printable recipe card at the bottom of the page.)

Equipment

  • 1 Large Sheet Pan (Baking Sheet)
  • Aluminum Foil (as needed)

Ingredients 

Instructions

  • Preheat oven to 375 degrees F.
  • Toss onions: Place onions, garlic and thyme on a large, rimmed sheet pan. Sprinkle with brown sugar, drizzle with 5 tablespoons of oil and season generously with salt and pepper. Toss everything together until evenly coated.
  • Cover the pan with foil and roast in the oven for 25 minutes, tossing once halfway through cooking. Remove foil and continue to cook for an additional 25-35 minutes, or until softened and golden in color, removing onions from the oven and tossing the onions 2-3 during cooking. If you prefer a darker color, switch the oven to broil and broil for 5 minutes – watch the onions carefully as they can easily burn!!
  • Remove the pan from the oven and discard thyme sprigs (SEE NOTES). Drizzle onions with Worcestershire sauce and/or Balsamic if using. Toss to combine.
  • Serve: Taste and adjust for seasoning with salt and pepper. Serve and enjoy!

Notes

  1. While yellow onions are my preferred onion to use, you can use whatever variety of onion you prefer – red, sweet or white works as well!
  2. 4 onions will seem like a lot on the baking sheet, but do not be alarmed. Onions will cook down by a ton (they will shrink to about a 6th of the amount).
  3. The brown sugar is optional. I used 1 ½ tablespoons because I like the extra depth of sweetness it gives the caramelized onions.
  4. I tossed my onions 4 times during baking. Please note, the more you toss the onions, the less likely the edges are to burn and the more evenly they will caramelize.
  5. If you don’t like roasted garlic, feel free to discard the cloves when you discard the thyme sprigs or you can keep them whole, mince or slice them.  I removed the cloves, thinly sliced them and then tossed them back in the onions before serving.
Recipe Serves: 6-8
Nutritional information is an approximation based upon 6 servings.  Exact information will depend upon the brands of ingredients and precise measurements used.

Nutrition

Calories: 178kcal    Carbohydrates: 12g    Protein: 1g    Fat: 14g    Saturated Fat: 1g    Sodium: 15mg    Potassium: 162mg    Fiber: 1g    Sugar: 6g    Vitamin A: 30IU    Vitamin C: 9.1mg    Calcium: 29mg    Iron: 0.5mg

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