Here’s how to caramelize onions that are sweet, savory, and silky, every time. Use this guide to slice, cook, and put those gorgeous caramelized onions to delicious use!
Looking for onions fast? Try my roasted onions or pickled red onions.
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Ingredient Notes
With only 2 ingredients, you can get silky smooth and slightly sweet caramelized onions. With a few additional ingredients, you can morph these onions any way you please. Here’s what to grab, and a few options:
Best onions for caramelizing
You can use any variety of onions when carmelizing, they’re truly all delicious. But, each has a slightly different flavor profile. Yellow onions are my preferred, here’s why and everything else you should know:
- Yellow or Spanish onions are best for caramelizing–their high sulfur content will give you the most balanced sweet and savory flavor profile.
- Sweet onions will get even sweeter when caramelized, and lack any savory notes–this may be good or bad, depending on how you plan to serve them! They also caramelize more quickly.
- Red onions are more mild than yellow, and, again, lack the savory note when sauteed. Caramelized red onions will pick up the most color.
Is it better to caramelize onions with butter or oil?
For optimal flavor and ease of cooking, I prefer using a combination of butter and oil. Here are the facts so you can decide:
- Opt 1: Butter + oil. This is the best way to infuse your caramelized onions with butter’s flavor, while not burning the butter.
- Opt 2: Oil only. Use vegetable or avocado oil, the goal is an oil with a high smoked point and mild flavor, i.e. not olive or coconut oil.
- Don’t: Use butter only. It burns easily and will ruin your caramelized onions.
How to Slice Onions
Slicing an onion can be hard! And after many years of doing it “the wrong way”, I want to share with you how to do it easily without any problems:
1. Slice off the stem of your onion.
2. Trim the root, keeping it intact (this makes the onions easier to slice),
3. Cut onion in half through the root.
4. Peel, remove, and discard the skin.
5. Make angular slices to cut your onion into slivers about 1/8″ thick, toward the center of the onion. Make sure not to slice through the root.
6. Finally, chop off the root, and separate the slices.
How to Caramelize Onions
As your onions continue to caramelize, you’ll notice their color, texture, and flavor will also transform. You can pull your onions once they’ve cooked to your liking, here’s a picture, and what to expect from each stage:
- 15-25 minutes: Your onions will still have a bit of crunch, but they’re slightly tender.
- 30-40 minutes: Softer and sweeter, these onions are ready for baked dishes.
- 45-50 minutes: Deeply caramelized, use these silky smooth onions for burger or sandwich toppings.
How to Caramelize Onions Quickly
Caramelizing onions low and slow is key in building the intricate flavor profile they have to offer. There are many “tricks” to caramelizing onions quickly, but most of them will prevent your onions from reaching that melty texture while trapping in their sugars. Here’s what you should know:
- Be OK with a bit of crunch, and a little less sweet. You can pull your onions as quickly as 15-20 minutes. You’ll find these have a bit of crunch, and won’t be as sweet as onions that cook longer. But that may work for you.
- Add a touch of brown sugar or balsamic. This will raise the pH of the onions, and allow their sugars to caramelize more quickly. That said, their flavor won’t develop the same, I don’t love doing this!
How to Use Caramelized Onions
Add your caramelized onions to just about any dish for a major flavor upgrade! Here are some of our favorite ways to use them:
- Burger or sandwich topping – caramelized onions and blue cheese on burgers are a must.
- Eggs – the perfect mix-in for omelets, scrambles, egg muffins, or frittatas.
- On a slice of toast, with a spread of ricotta.
- Mixed into grains or pasta with some roasted vegetables, your favorite sauce, or cheese.
Pro Tips
Sometimes the simplest recipes are the most complicated–and although making caramelized onions can be easy, there are a few important tips to keep in mind:
- Don’t slice your onions too thin – this makes them more susceptible to burning.
- Make a big batch – since this process takes a whileee, I like whipping up a big batch to make the most of my time.
- Deglazing is key in developing the flavor–this is how you’ll remove the fond (little brown bits that are full of flavor) from the bottom of the pan and incorporate them into the sauce.
- Remove when you’re ready – see notes above, and taste test for yourself. Cliff notes: if you want melty onions, keep them on for the full 45 min – 1 hour.
More Veggie Sides
- Fried Green Beans
- Grilled Portobello Mushrooms
- Jicama Fries
- Roasted Broccolini
- Mashed Butternut Squash
How to Caramelize Onions
Print Recipe Pin RecipeIngredients
- Yellow Onions depending on your pan size and the size of your onions, I typically cook 3 medium onions in a large pan.
- Vegetable oil, optional to add 1 teaspoon of butter per onion
- Water
Instructions
- Slice your onion into even pieces that are no smaller than 1/8" thick. To do this, remove the stem, and slice the tip of the root (leaving the root intact). Slice your onion in half. Now, make angular cuts to slice your onion into 1/8" slices almost all the way through, but not slicing the root. Finally, chop off the root, and break your onion into pieces.
- Heat your pan over medium heat, and add oil, you want enough to coat the bottom of your pan in an even layer. Once shimmering, add your onions, and butter (if using). Stir to coat the onions in oil.
- Continue cooking, and stirring your onions as they soften. Sprinkle with salt. As soon as your sliced begin to look dry, add a splash of water and toss to coat–I usually start adding water around 25 minutes. Continue to cook and stir your onions until they're brown and caramelized, this should take between 45 minutes – 1 hour.
When you make a big batch, how do you store the extra until you’re ready to use it? How long will it keep?
Hi Myra! I try to eat them within 4 days, and I store them in an airtight container in the fridge. Enjoy!