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Get ready to transform basic onions into a rich, golden-brown treat with this easy recipe and kitchen hack for caramelizing onions in the oven. This guide will show you the simpler, hands-off way to make sweet, savory, deeply flavorful caramelized onions – the oven! Plus, I’ll answer all your burning questions, like how long to cook onions in the oven and what temperature works best for perfect results.

“Since I found this recipe = Game Changer for doing large batches of caramelized onions. They always come out perfectly and the house smells divine! Thank you for posting this amazing recipe.”

– KATHY
Overhead photo of onions caramelized in the oven on a parchment-covered baking pan.

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

Table of Contents

About this recipe 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!

Why use the oven to caramelize onions?

While caramelizing onions on the stovetop is a classic method, it also requires constant stirring and attention. Baking onions in the oven, on the other hand, allows you to set them and forget them – freeing you up to focus on other tasks while the oven does all the hard work.

Plus, the even heat distribution from the oven helps the onions caramelize uniformly, which creates rich, buttery-tender, magically-sweet strands without the risk of burning or uneven cooking.

5 reasons to caramelize onions in the oven (instead of other methods)

  • Mostly Hands-Off, Effortless Cooking. Unlike stovetop methods that require constant attention and stirring, caramelizing onions in the oven is a more hands-off approach. Once the onions are prepped and in the oven, you can set a timer and focus on other aspects of your meal without the fear of burning
  • Even, Consistent Caramelization. When you roast onions in the oven, the heat is evenly distributed, which ensures that all the slices cook uniformly and turn  consistently golden.
  • Perfect for Large Batches. If you’re making a big batch of caramelized onions for meal prep, soups, or sauces, the oven method is ideal. You can easily caramelize onions in the oven in large quantities without worrying about overcrowding a pan or dealing with multiple batches.
  • Minimal Cleanup. Baking onions in the oven means fewer pots and pans to clean. All you need is a single baking sheet and parchment paper, aluminum foil, or a silicone mat for easy cleanup. 
  • So Much Flavor. The slow and steady oven cooking process allows the natural sugars in the onions to break down and concentrate more thoroughly than quick stovetop methods. The result? A profound, rich sweetness and complex umami flavor.
Angled action photo of oil being drizzled over raw, sliced onions before caramelizing in the oven.

Ingredients for caramelized onions in oven

  • Yellow Onions. Yellow onions are perfect for caramelizing, offering a balance of sweetness and savory depth. Choose firm, unblemished yellow onions with dry, papery skins. Avoid onions with green shoots, as they can be bitter.
  • Garlic. Garlic adds a warm, aromatic note to the caramelized onions. When roasted, it turns sweet and mellow, complementing the richness of the onions.
  • Thyme Sprigs. Fresh thyme introduces a muted earthy, slightly floral flavors that pair beautifully with the sweet and savory onions. If you can’t find fresh thyme, you can substitute with 1 teaspoon of dried thyme.
  • Light Brown Sugar. Brown sugar enhances the natural sweetness of the onions, promoting the caramelization process. Ensure the brown sugar is soft and moist, as hard lumps indicate that it has dried out.
  • Olive Oil. Oil add richness and helps the onions cook evenly and caramelize beautifully, without burning. 
  • Kosher Salt and Ground Black Pepper. Kosher salt enhances the sweetness of the onions and helps draw out moisture for a better caramelization. And the black pepper adds a touch of mild spice and balances the sweetness.
  • Optional – Worcestershire Sauce. While optional, Worcestershire adds a savory, umami-rich depth of flavor to the onions.
  • Optional – Balsamic Vinegar. While optional, balsamic lends a touch of sweet acidity that balances the richness of the caramelized onions.

Recipe variations

Caramelized onions are a super versatile ingredient and you can customize them in many ways to suit your personal tastes. Below are a few variations on the basic recipe that you can try:

  • Balsamic and Honey Caramelized Onions. Swap out the sugar for honey and drizzle the onions with balsamic reduction before serving for a glossy, sweet finish.
  • Smoky Caramelized Onions. For deep, smoky flavor with a tiny touch of heat, add a little smoked paprika or a dash of chipotle powder for smokiness. And incorporate a drop or two of liquid smoke for a stronger smoky flavor.
  • Balsamic and Mustard Caramelized Onions. If you’re looking for a piquant-depth of flavor, add a teaspoon of dijon mustard to the raw onions before roasting. And then finish the baked onions off with a drizzle of balsamic vinegar.
  • Herbed Caramelized Onions. For a lighter, more vibrant flavor, use a mix of fresh herbs like rosemary, oregano, or sage alongside the thyme sprigs.
  • Caramelized Onions with Bacon. Add a punch of delicious umami flavor baby swapping the oil for bacon grease. Just be mindful of the kosher salt, as bacon can be quite salty so you may want to consider reducing it.
  • Sweet n’ Spicy Caramelized Onions. For a sweet and spicy flavor profile, add a pinch of cayenne pepper or crushed red pepper along with the sugar.
  • Wine-Infused Caramelized Onions. Try adding a splash or two of red wine or white wine to the onions halfway through caramelizing for a rich, complex, and slightly tangy flavor.

Follow these chef expert tips for best success!

  • Choose the Right Onion. Use yellow onions for the ideal balance of sweetness and savory flavor. They have the right amount of sugar to caramelize, turning sweet and golden when roasted. However, you can use whatever variety of onion you prefer – red, sweet or white works as well.
  • Slice Evenly. Consistent slices ensure that all the onions cook at the same rate, giving you even caramelization.
  • Season Generously. Salt helps draw out moisture for better caramelization, while black pepper adds balance to the onion’s sweetness.
  • Add Sweetness (Optional). A little brown sugar helps enhance caramelization and gives the onions a rich, golden-brown color.
  • Use Fat. Olive oil helps the onions cook evenly and contribute a delicious smooth flavor. 
  • Don’t Overcrowd the Pan. Try to arrange the onions in a single layer on a large, rimmed baking sheet. If you want to double the recipe, I recommend using two pans.
  • Toss Often. The more you toss the onions, the less likely the edges are to burn and the more evenly they will caramelize. I toss mine about 4 times during baking.
  • Add Optional Flavor Enhancers. For added flavor, drizzle a little balsamic vinegar and Worcestershire sauce over the onions at the end of roasting.
  • If you don’t like garlic, feel free to discard the roasted 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.
Close-up photo of raw, thick-sliced onions topped with sprigs of thyme, brown sugar, cloves of garlic, salt and pepper.

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.

Do I need to use oil or butter to caramelize onions in the oven?

Yes, it’s imperative to use a fat like olive oil or butter to help the onions cook evenly and develop a rich, golden-brown color. Both fats – oil or butter – will add flavor; however, the oil will provide a lighter finish and the butter will give a creamier texture.

Can I caramelize onions without sugar?

Sure. Onions naturally contain sugars that will caramelize as they’re slowly cooked. The light brown sugar is technically optional. However, it does help accelerate the caramelization process and enhances the sweetness, especially if you prefer a deeper caramel flavor.

How do I prevent my onions from burning in the oven?

To prevent burning, make sure you stir the onions every 15-20 minutes to ensure even cooking and caramelization. Also, make sure you’re roasting at 375°F —if the heat is too high, the onions can burn before they fully caramelize. Lastly, keep an eye on them in the final 10-15 minutes to avoid overcooking.

How long does it take to caramelize onions in the oven?

It typically takes about 60 to 75 minutes at 375-degrees Fahrenheit for onions to caramelize in the oven. The precise cooking time will vary slightly depending upon the thickness of your onion slices and the calibration of your oven.

How do I know when my onions are done caramelizing?

Caramelized onions definitely require patience – so don’t rush the process. Your onions are done when they’re deep golden-brown in color, very soft in texture, and sweet in flavor. When you take a bite, the onions should have a rich, slightly jammy texture with a delicious pronounced sweetness. If the onions are pale in color or crunchy in texture, then they need more time roasting in the oven.

Serving suggestions

Now that you know exactly how to caramelize onions in the oven, it’s time to enjoy them – yay! Below are a few delicious ways to incorporate this caramelized goodness into your meals:

Common ways to use caramelized onions

  • Make a Creamy Dip. Finely chop the baked onions and add them to your favorite creamy dip base to make caramelized onion dip. Or tuck them into the best fried pickle dip for a touch of sweetness.
  • Use it for French Onion Soup. Make a flavorful soup base with beef stock, sherry, and fresh thyme. Stir in the caramelized onions and simmer for a quick and easy onion soup.
  • On Burgers. Add a generous scoop of caramelized onions on top of your favorite burger for an extra layer of sweetness and savory depth. The rich, tender onions elevate any ground beef burger, chicken, or veggie bean patty.
  • On Sandwiches. Layer jammy onions onto sandwiches or paninis for a mouthwatering addition. They pair beautifully with meats like roast beef, deli turkey meat, or poached chicken, as well as vegetarian options like grilled cheese or veggie melts.
  • On Pizza. Caramelize onions and use them as a topping on pizzas. They complement toppings like goat cheese, mushrooms, and bacon.
  • With Roasted Meats. Serve the roasted onions as a side to roasted meats like beef, apple pork tenderloin, or whole roasted chicken. Their sweet-savory balance is the perfect complement to the savory richness of meats.

Unique suggestions

  • On Charcuterie Boards. Incorporate oven caramelized onions onto a charcuterie board, where they pair well with cheeses like cheddar, blue cheese, and baked brie en croute. They also go wonderfully with cured meats like prosciutto or salami, and bite-size apps, like goat cheese phyllo appetizer.
  • As a Topping for Mac & Cheese. Add a spoonful on top of creamy butternut macaroni and cheese for an unexpected burst of sweetness and texture. It’s an irresistible combination of flavors.
  • With Eggs. Soft onions make a fantastic topping for scrambled eggs, omelettes, or frittatas. Their sweetness balances the richness of eggs, creating a flavorful breakfast or brunch dish. I personally love them in this crustless spinach bacon quiche.
  • In Soups and Stews. Stir oven onions into your soups and stews to add a deep, interesting flavor. I love adding it to apple soups, and this pasta with ground sausage.
  • Stir into Pastas. Add depth and richness to your favorite pastas, sausage zitis. and risottos, like this risotto with butternut squash or risotto scallops, by stirring in the cooked onions or using them as a garnish. I like to use any leftover sweet onions to make this ultra-delicious cheesy baked gnocchi.
  • In Tacos or Quesadillas: Add roasted onions to tacos or quesadillas for a gourmet touch. They pair especially well with Carolina pulled pork, chicken, or grilled vegetables, adding sweetness and a savory boost.

Storing leftovers

Refrigerator storage

  • How to Store: After caramelizing the onions, allow them to cool completely before transferring them to an airtight container or glass jar.
  • Shelf Life: Store in the fridge for 4 to 5 days.

Freezing instructions

  • How to Freeze: After cooling, spoon the caramelized onions into a freezer-safe container or resealable plastic bag. If using a bag, be sure to flatten it out to remove excess air before sealing to prevent freezer burn.
  • Shelf Life: Store the onions in the freezer for up to 3 months.
  • Tip: For easier portioning, consider freezing the onions in small amounts or use an ice cube tray to freeze individual servings. Once frozen, transfer the cubes to a bag for easy use.
  • Using: Frozen caramelized onions do not need to be thawed! You can simply use them in a recipe as is.
Close-up photo of thinly sliced yellow caramelized onions with garlic and fresh thyme.

With the same delicious flavor and half the effort and mess, these oven caramelized onions are a cooking game changer! Until next time, friends – to cooking hacks and jammy onions.

Cheyanne

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More onion recipes!

Overhead, close-up photo of caramelized onions made in the oven.

Caramelized Onions in Oven

5 from 11 votes
Author: Cheyanne Holzworth
Total Time: 1 hour 5 minutes
Prep Time: 10 minutes
Cook Time: 55 minutes
Servings: 6 servings
Print Recipe Pin Recipe
Get ready to transform basic onions into a rich, golden-brown treat with this easy kitchen hack for caramelizing onions in the oven. This guide will show you the simpler, hands-off way to make sweet, savory, deeply flavorful caramelized onions – the oven! Plus, I'll answer all your burning questions, like how long to cook onions in the oven and what temperature works best for perfect results.

Equipment

  • 1 Large Sheet Pan or Baking Sheet – with Aluminum Foil

Ingredients 

Instructions

  • Preheat the Oven: Arrange the oven rack to the center position and then preheat the oven to 375 degrees F.
  • Season the Raw 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 and Caramelize the Onions in the Oven: Cover the pan with aluminum foil and then place the onions into the preheated oven. Roast for 25 minutes, tossing once halfway through cooking.
    Remove the aluminum foil and discard it.
    Return the onions to the oven and continue to bake – tossing the onions 2 or 3 times during cooking – for an additional 25-35 minutes, or until the onions are soft, caramelized, and golden in color.
    (Note: 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!)
  • Flavor the Caramelized Onions: Remove the onions from the oven and place the pan on a wire rack.
    Remove and discard the thyme sprigs (SEE NOTES).
    Drizzle the top of the onions with Worcestershire sauce and/or Balsamic vinegar, if using. Then use two forks or spoons and toss to combine.
  • Serve Oven Caramelized Onions: Taste the onions and adjust for seasoning with salt and pepper. Serve immediately and enjoy!

Notes

  • 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.
  • 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).
  • The brown sugar is optional. I used 1 ½ tablespoons because I like the extra depth of sweetness it gives the caramelized onions.
  • 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.
  • 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.
  • Got questions? I’ve got answers! If you ever run into an issue, have a question, or need any clarification – please feel free to drop them in the comments section. I’m happy to help when I can! 
  • Recipe Serves: 6-8
Nutritional information is provided as a courtesy and the nutrition facts are an estimate based upon 6 servings. Exact information will depend upon the brands of ingredients and precise measurements used.

Nutrition

Calories: 158kcal    Carbohydrates: 13g    Protein: 1g    Fat: 12g    Saturated Fat: 2g    Polyunsaturated Fat: 1g    Monounsaturated Fat: 9g    Sodium: 19mg    Potassium: 172mg    Fiber: 2g    Sugar: 7g    Vitamin A: 35IU    Vitamin C: 9mg    Calcium: 33mg    Iron: 1mg
Course: Side Dish
Cuisine: French

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