I always joke that if I could make a custom Yankee Candle, it'd be sautéed onion-scented. It may sound odd, but in my opinion, there are few smells more enticing than that of onions (and garlic while we're at it) cooking down. For most of my childhood, that meant something was happening in the kitchen, and something good at that.
These days when I cook for myself, I don't do the traditional meal prep, but I do like to prepare some components to help me iterate on lunches and dinners throughout the week. One of the most frequent things I do is make a big batch of caramelized onions for two reasons. The first is that everything is better with caramelized onions; chicken, burgers, dip, quesadillas—you name it.
The second reason is that truly caramelized onions take a long, long time. Luckily, I found a hack that cuts the time down by half and even makes them weeknight-friendly, meaning you have a delicious, cheap dinner upgrade in your back pocket any time you need it.
How to Caramelize Onions Fast
Caramelizing onions can be a painstaking process that, if done the right way, can take well over an hour, even if you use a hands-off method like the slow cooker. To understand why, let's get into a quick science lesson.
Onions (like all vegetables) have lots of naturally occurring sugars, and cooking over heat draws out those sugars alongside amino acids to caramelize them, which is what causes the onions to take on a darker brown color and sweeter flavor. Cook onions too little, and they won't have enough time to develop that sweetness; cook them too hot and those sugars can burn. However, there's one simple step you can take that will not only speed up the process but make it more fool-proof, too.
I first learned this tip from Cooks Illustrated, and have been using it regularly since. Typically, you start with a pan, then add butter or oil and your onions and sauté on low heat until they start to cook down, stirring constantly. In this method, you add the onions to a skillet (preferably nonstick) with a little oil and salt and notably, water. About 1/2 cup is good for a big batch of onions. Once the water is boiling or close to it, put a lid on the pan so the onions can steam.
This essentially massively speeds up the process of wilting the onions, which can be the first 15-20 minutes of the sautéing process. And what's more, the water at the bottom becomes infused with all the sugary onion juices, distributing those sugars evenly through the onions. The resulting onions are softened in a matter of minutes, leading to caramelized onions in a few more.
You can also use vegetable, chicken, or beef broth in place of water for extra flavor. Adding the liquid gives you more leeway to walk away from the pan for a minute or two and not worry about whether the onions are going to burn. However, if at any point the pan does look dry, add a little more water (or broth or a splash of wine) to deglaze the pan, and keep stirring. Once the onions are softened and starting to brown, stir continuously until you reach your desired browning.
You can watch the full technique here, but really, just following this one step of liquid at the start of the cooking process will drastically reduce the total time.
This is one of those tips that will truly change the way you cook. Even if you don't want to take your onions to a stage of deep caramelization, it will cut down the prep time for any onion and make your weeknights *that* much faster and easier.
FAQs
A pressure cooker is yet another avenue often used for quick caramelized onions. The science is there: browning reactions happen faster at higher pressure, such as inside a pressure cooker. And if you test it out, you'll find that the science works. A pressure cooker can indeed speed up caramelized onions.
What is the science behind caramelizing onions? ›
Amino acids play a vital role in the chemistry of caramelization. When you fry an onion, the amino acids in the onion react with the heat to create new compounds that give the onion its brown color. This process is known as the Maillard reaction, and it's responsible for the flavor and color of many cooked foods.
What is the trick to caramelizing onions? ›
The trick is to leave them alone enough to brown (if you stir them too often, they won't brown), but not so long so that they burn. After the first 20 to 30 minutes you may want to lower the stove temperature a little, and add a little more oil, if you find the onions are verging on burning.
What makes onions caramelize faster? ›
So adding water and covering the skillet causes the raw onions to wilt faster and more evenly as the water turns to steam. Then, uncover the skillet and begin a process of pressing the softened onions into the bottom and sides of the skillet for maximum contact—and maximum browning.
What is the best liquid to caramelize onions in? ›
You can use just oil, or a combination of butter and oil—the choice is yours! If you pack too many onions into your pan, they'll steam and produce water. Eventually, they will caramelize—but it will take much longer to get them there.
What is the science behind browning onions? ›
As onions cook, the heat breaks down their cellular structure, releasing sugars and amino acids. These compounds then react with each other, forming the Maillard products responsible for the delightful aroma and taste of caramelized onions.
Do onions caramelize better with butter or oil? ›
Our Test Kitchen likes to use butter when caramelizing onions, as it offers the richest flavor. If you avoid dairy or don't have butter, you can caramelize onions in other fat such as margarine or olive oil. Add the onion slices. It's okay if they overlap a bit here because they'll shrink as they cook down.
Why are my onions taking so long to caramelize? ›
Before onions can caramelize, enough moisture has to evaporate out of the pan for the cooking surface to climb above 212 degrees. That alone takes a while, and once it happens, you're still committed to stirring and scraping so the onions' natural sugars break down evenly.
What is the science behind cooking onions? ›
Caramelizing or sauteing onions on low or moderate heat causes a reaction between the sugars and the proteins. The onions turn brown, the sugars come free, and the sulphuric compounds react over and over until the pungent flavor is gone and the sweet sugar flavor remains.
Should you salt onions before caramelizing? ›
Salting caramelized onions is like the icing on the cake. They must have salt but don't make the mistake of salting the onions too early. Instead, salt them at the very end of the recipe. Salt makes the onions release moisture which can slow down the caramelization.
Simply put, caramelized onions aren't quick. It takes at least 45 minutes (and often over an hour) over low heat for the natural sugars in the onions to caramelize. Still, the time is totally worth it. Packed with irresistible umami flavor, caramelized onions add complexity to all sorts of savory dishes.
Why add baking soda to caramelize onions? ›
Baking soda makes the onions more alkaline, which speeds up the browning reactions necessary for properly caramelized onions. But it also weakens the pectin that holds the onion's cells together, turning what should be soft but distinct pieces of browned onion into a nauseating stew of pea-green mush.
Why do you add sugar to caramelize onions? ›
And adding sugar will make your onions sweeter. So if sweetness is what you're going for, do it my friends! I personally don't add any sugar to my onions. While I love sweetness as much as the next kid, the extra sugar makes the caramelized onions more one noted in my opinion.
What is the secret to caramelize onions? ›
How to Caramelize Onions Fast
- Add sugar: some cooks swear by adding a pinch of sugar to enhance the onions' sugar content and help them caramelize faster.
- Add baking soda: dissolve a 1/8 teaspoon baking soda in 1 tablespoon of water and add the mixture to the onions toward the end of cooking (about 15 to 20 minutes in).
Cover the pot with a lid, and then turn the burner on to medium-low heat. Cook covered until the onions have mostly broken down and are a pale brown sludge (about 45-60 minutes). Be sure to stir the pot periodically, checking to make sure the onions aren't burning.
How to tell when caramelized onions are done? ›
Caramelized onions should be far darker than golden in color. → Follow this tip: Cook times will vary depending on the number of onions you're cooking and the type of onion (its sugar content and age), but plan to cook caramelized onions for 40 to 50 minutes (at least) until they have a dark-brown, rich color.
What is the chemistry behind caramelization? ›
Caramelization is what happens when any sugar is heated to the point that the molecules undergo chemical reactions with oxygen in the air and with each other – the molecules either break apart into smaller molecules, or combine with one another to make larger molecules.
Is caramelizing onions physical or chemical? ›
The term caramelizing onions is actually a bit misleading as there are multiple chemical reactions taking place side by side that lead to the gorgeous brown color and deep flavors that we attribute to the caramelization of onions.
Are caramelized onions the Maillard reaction? ›
As moisture is released—fresh onions are nearly 90 percent water—and the onion's natural sugars slowly heat up, they caramelize, while the onion simultaneously undergoes a chemical reaction known as Maillard browning.
