Tips & Techniques

How to Achieve Perfectly Caramelized Onions

June 26, 2013

Inspired by conversations on the Food52 Hotline, we're sharing tips and tricks that make navigating all of our kitchens easier and more fun.

Today: Deeply caramelized onions take little more than time -- and a little patience. 

Cooking can often seem like the most wonderful mix of science and magic. Soft, pillowy cakes arise from the runniest of batter, while unruly vegetables cook down into tame, tender versions of their former selves. The caramelization of onions is decidedly scientific -- involving glucose, cell structures, and the beloved Maillard reaction -- but the results are nearly magical. 

Let's get started. You'll first need to choose your onions: yellow is recommended, as it contains a high amount of pungent lachrymators (the compounds that make you cry), which produce a mellow, yet complex end product.  

You can use as many or as few onions as you'd like, keeping the size of your pan in mind. Of course, remember that your onions will cook down quite a bit (they're mostly water, after all), and that they're a delicious addition to almost anything. 

You'll want to cut your onions in half, peel them, and then remove the root and top ends. Lay the halves down, and make thin slices, either across the bulb to form half rings, or vertically from root to stem. Due to the cell structure, slicing across will yield an end product with a bit more texture than the jam-like result of slicing vertically. Next, get ready for the two stages of caramelized onions. 

 

Grab a wide, thick-bottomed stainless steel or cast iron pan, and add enough oil or butter to coat the bottom -- about 1 teaspoon per onion. Heat the oil or butter over medium-low heat, and throw in your onion slices. The onions will begin to 'sweat' and soften as water exits the cells. Stir occasionally, and after about 10 minutes, or when the onions are soft and most of the moisture is gone, add a pinch of salt.

At this point, you may need to reduce the heat to keep the onions from burning. The onions will begin to take on color as the sugars oxidize, indicating that caramelization has begun. Let them continue to cook for 30 minutes to one hour, stirring often enough that they don't burn, but not so much that they won't brown.  

When the onions are uniformly a deep, rich brown, the process is complete! Some people elect to deglaze the pan at this point with a little balsamic vinegar or wine to add extra flavor, however it's not necessary. Now that you know how easy it is to make this multi-tasking ingredient, prepare it in bulk, and add to salads, soup, sandwiches and pizza -- in short, everything you can think of. 

How do you use caramelized onions? Let us know in the comments!

20 Comments

allis February 25, 2017
I have been making caramelized onions in large batches and freezing them for years! I didn't really like onions much until I had these. They give all kinds of foods such wonderful depth of flavor! I especially love them in soups and egg dishes like quiches and frittatas, but use them in almost anything that calls for onions. I use a lot more oil than you need because it takes on the delicious flavor and is useful in dishes that don't have a lot of fat in the recipe.
 
lynda September 28, 2016
I thought slicing across yielded a more jam-like end product than slicing vertically ...
 
Emmett M. May 1, 2016
This seems like the way I start my french onion soup, butter and onions, cook until dark brown but not burned and you have the beginning of a delicious soup
 
Les N. January 23, 2016
On pizza with figs and gorgonzola, with arugula finish... it's the best
 
Sandra R. January 20, 2016
I use my slow cooker, using Spanish yellow onions. It takes all day but is easy, give it a stir every hour or so, leave the top ajar at the end. And I freeze them, in bags of one cup for soups and stews later, and in ice cube trays for little bits, like eggs or sandwiches. It is a lovely winter thing to have on hand.
 
mela February 1, 2018
I use the slow cooker for this too, but don't have to stir following the instructions in one of the Cooks Illustrated cookbooks. Their method also lessens the smell, which I found pretty horrific using other methods. Haven't tried yours though, that may be next.
 
radovanovic.rade September 8, 2014
How it is kept in restaurant conditions and for how long? Thanks a lot!
 
jackie September 7, 2014
Just eat them by the spoonful or spread on a good cracker.
 
Julia W. June 22, 2014
Today is "Cook the Fridge" day at our house: which means the caramelized onions are joining roasted butternut squash, bacon and beer in a risotto -- veggie stock from the balance of our crisper drawer currently simmering….
 
Stacy February 2, 2014
I love all things caramelized onion. I see that yellow onions are recommended... but as a girl still scarred from a week long "onion breath" episode, I was wondering if anybody knows which onions to avoid using? (Seriously! It was quite the debacle.)<br /><br />Thanks in advance if anybody can answer this question!
 
Deidre G. June 26, 2013
One of the readers comments that she freezes the onions when she prepares them in bulk. Any other suggestions? And how long do they last in the fridge?
 
Blissful B. June 26, 2013
I love caramelized onions, and I love that you told the truth about how long it takes! This article makes me laugh because it's so often true in recipes: http://www.slate.com/articles/life/scocca/2012/05/how_to_cook_onions_why_recipe_writers_lie_and_lie_about_how_long_they_take_to_caramelize_.html
 
chocbird09 August 10, 2013
I thought I'd share this: https://www.stellaculinary.com/podcasts/video/how-to-caramelize-onions-in-10-minutes-or-less-a-rebuttal<br /><br />Please note, before someone starts trying to shoot me over the Internet that these can't taste like onions done traditionally, Mr. Burton says (in a comment): "I haven't done a blind taste test and I wouldn't go as far as saying that these onions are better then the ones cooked over slow heat for 45-60 minutes. If I were to make a classic French Onion soup, I would most likely caramelize my onions over a long period of time.<br /><br />My issue with Scocca's article wasn't that he said caramelized onions that are cooked for at least 40 minutes are better; my issue was with him saying "It's never been done" and it is "impossible." "
 
laughing June 26, 2013
I've done them in a slow cooker - no stirring necessary! It makes the whole house smell amazing, and it's easy to make a huge batch and freeze the extra.
 
Fred R. June 26, 2013
I add a few Tbs of water and a lid for the first 10 min. The steam kills the cells quickly allowing water to escape and beginning the caramelization process sooner....still should take one and a half hours to do it right.
 
Nancy M. June 26, 2013
Mix a half cup of caramelized onions with 2 tablespoons of creme fraiche, add a pinch of thyme and toss with some fettucine, and you will have the yummiest thing you ever ate. Not the most attractive thing, but yummy nonetheless.
 
Rivka June 26, 2013
I recently changed the way I caramelize onions after finding a Thomas Keller tip in Ad Hoc at Home. For Leek Bread Pudding, he has you start the leeks in a dry pan, which essentially reduces the maximum temperature of the pan's surface to 212 degrees (the temperature of steam) as opposed to in the 350-450 neighborhood (smoking point of oil). As a result, the leeks cook more slowly and evenly, even when the heat is medium-high. The technique works wonders for onions as well. Once the onions have softened a bit and become translucent, I add oil and/or butter, and cook as I normally would - but the dry pan speeds up the process and prevents scorching.
 
Trena H. June 26, 2013
Thanks for the tip!
 
Pegeen June 27, 2013
That's a very interesting tip. Thanks!
 
minibakersupreme March 9, 2016
@Rivka, I know your comment was three years ago (!) but I just tried your dry pan tip, and it was awesome! Thanks for the comment.