How to Make Caramelized Onions (Perfectly)
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I’m a little obsessed with caramelized onions. They turn the simplest dish into something special and you don’t need a single pinch of sugar to get there.
Here’s the thing: when you cook them right, onions caramelize all on their own. Their natural sugars come out slowly as they cook, and that’s exactly where that deep, sweet flavor comes from. Best of all, it’s genuinely easy, it just takes a little patience. Here is the recipe to get them perfectly caramelized every time!
In This Post
- How to Make Caramelized Onions (3 Keys to Getting It Right)
- Caramelized Onions Recipe Card
- Best Onions to Caramelize (and Which to Avoid)
- Do You Need Sugar to Caramelize Onions?
- How Long Does It Take to Caramelize Onions?
- What to Serve with Caramelized Onions
- FAQ About Caramelized Onions
- More French Cooking Basics
How to Make Caramelized Onions (3 Keys to Getting It Right)
If there are just three things you should keep in mind before starting to caramelize your onions:
- Take your time: that’s really the only secret. The longer you let your onions cook over low heat, the more caramelized they’ll be and the more intense their flavor will be. If you turn up the heat to speed things up, your onions may burn and develop a bitter taste.
- Add salt right from the start: the salt will help the onions release their liquid, and they’ll soften faster.
- Deglaze with cold water: As soon as the bottom of the pan starts to stick, add a little cold water. Then, scrape up the browned bits (the little bits stuck to the pan)—that’s what gives your caramelized onions that intense flavor.
When are my caramelized onions ready? To be honest, it’s up to you. The longer you leave them, the more flavor they’ll have. I usually stop when they’ve turned a nice dark color and are nice and shiny. This takes about 45 minutes.
Caramelized Onions Recipe Card
Caramelized Onions
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Ingredients
- 1.8 lb yellow onions 800 g, finely sliced
- 2 tbsp olive oil
- ½ tsp salt
- 1/2 cup water to be added gradually while cooking
- 1/2 tbsp butter
- 1 tbsp balsamic vinegar optional
Instructions
- Slice the onions into even strips so that they all cook at the same rate.
- Heat the oil in a large skillet over medium heat, add the onions and salt, and cook for 5 to 8 minutes, until they become translucent.
- Reduce the heat to low and let them brown, stirring only occasionally. As soon as they start to stick, add a tablespoon of cold water, scrape up the juices with a wooden spoon, and then stir. Repeat every 10 to 15 minutes.
- Allow 45 to 60 minutes total to achieve a nice color. The onions will shrink to 1/4 to 1/5 of their original volume—that's normal!
- Remove from the heat, add the butter and balsamic vinegar, stir, and taste.
Notes
Nutrition
Best Onions to Caramelize (and Which to Avoid)
Caramelized onions work with any kind of onion: yellow, white, or red. You can even mix them together.
Yellow onions are the most common. Red onions, on the other hand, have a darker color and a slightly sweeter taste. Personally, I often use large yellow onions because they’re quicker to chop! The only onions that don’t work very well are spring onions and scallions.
Note: You’ll notice that caramelized onions shrink significantly in volume, so from experience, I always cut a little more than I plan to use!
Do You Need Sugar to Caramelize Onions?
A lot of recipes tell you to add a spoonful of sugar to caramelize the onions, but you really don’t need to.
Onions are already full of natural sugar, and cooking them over low heat for a very long time brings out that sugar and creates that subtle, natural caramelized flavor. Added sugar mainly causes the surface to brown quickly—it doesn’t give you that deep, melt-in-your-mouth flavor we’re looking for.
How Long Does It Take to Caramelize Onions?
I might as well be honest with you: to get truly caramelized onions, it takes at least 35 to 45 minutes. Those famous “10-minute” recipes just give you onions that are golden brown, not caramelized. They’re good too, but it’s not the same thing.
But once you’ve started cooking them, you can leave them on very low heat without watching them and come back to stir them every 15 minutes.
Quick Method with Baking Soda: There’s a time-saving trick if you really need it. Add a small pinch of baking soda (a pinch (about ¼ tsp) per pound of onions) once they’re translucent. The baking soda speeds up the browning process significantly, and you can reduce the cooking time to just 15–20 minutes.
How to Store and Freeze Caramelized Onions
When I do my caramelized onions, I love to make a big batch to store or even freeze them for later. It’s always good to have some on hand. Here is how best store them:
- In the fridge: 4 to 5 days in an airtight container. Pour a thin film of olive oil over the top, and they will last a full week.
- Always chilled: onions stored in oil should never be kept at room temperature; there’s a real bacterial risk.
- In the freezer: portion them into an ice cube tray, one to two tablespoons per slot, then move the cubes to a freezer bag. Three months, no problem.
- No ice cube tray? Press them flat in a freezer bag and snap off a piece when you need it.
- To reheat: no need to thaw. Drop them straight into your pan, your soup or onto a pizza.
What to Serve with Caramelized Onions
The great thing is that caramelized onions go with almost anything! My favorite ways to use them in the kitchen:
- They are the base for the famous French onion soup!
- In a quiche or a pizza to add flavor.
- With pasta, such as my pasta with Italian sausage
- Spread on a slice of toast with fresh goat cheese and figs.
- In France, we also use them as a topping for the buckwheat Galette (French savory cêpes), with an egg and a little cheese.
- In my zucchini savory cake or served over creamy polenta with Parmesan.
And if you love caramelized onions, you’ve got to try my caramelized onion Tarte Tatin or the famous pissaladière, a tart with caramelized onions and anchivies from the south of France.
FAQ About Caramelized Onions
Most of the time, it’s because your heat is too high. To caramelize the onions without burning them, you absolutely must cook over medium-low heat and deglaze with water as soon as the bottom starts to stick. .
No, don’t boil them in a pot of water—you’ll lose their natural sugars and flavor in the cooking water. The best approach is to sweat them, covered, with just a little moisture, then uncover them to brown them. That way, you’ll tenderize them without wasting anything.
Absolutely, and that’s actually a great idea. Prepare them the night before, store them in the fridge in a sealed jar, and gently reheat them in a skillet just before serving.
Yes, they freeze very well. I divide them into an ice cube tray to make small portions, then transfer them to a freezer bag. It’s handy for making soup or a quick pie.
Yes, maybe at the beginning to help the onions shrink quickly, but only for the first 5 minutes. After that, uncover the pot so the water can evaporate and the onions can brown.
