Balsamic Caramelized Onions | The Best Caramelized Onions Recipe (2024)

FAQs

Is it better to caramelize onions 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.

You can caramelize any kind of onion, but yellow or Spanish onions tend to offer the most balanced-sweet-savory flavor profile and are the most versatile for different dishes. Sweet onions, such as Vidalia or Walla Walla work too, but keep in mind that their flavor will become even sweeter once caramelized.

This is our secret ingredient to make the best caramelized onions. Vinegar adds a touch of acidity to balance out the sweetness of the onions. It elevates their flavor wonderfully. We recommend balsamic vinegar if you use red onions and apple cider vinegar if you use white or yellow onions.

Continue stirring and scraping the onions every minute or two, keeping an eye for signs of browning on the bottom of the pot. When the browning starts speeding up, it's best to lower the heat to keep the transformation slow and even.

In addition to water, we have another secret ingredient: baking soda. We often turn to it to speed browning, since it creates a high-pH environment, which allows caramelization to occur more readily. Baking soda is also handy for softening vegetables because altering the pH helps weaken their cell structure.

You're not sautéing your onions—you're trying to slowly coax flavor out of them. It takes time, probably a solid 45 minutes, for the onions' sugars to caramelize. If your heat is too high, the onions will burn. Heat your pan over medium-low, then add your onions.

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.

After 10 minutes, sprinkle some salt over the onions, and if you want, you can add some sugar to help with the caramelization process. (I add only about a teaspoon of sugar for 5 onions, you can add more.) One trick to keeping the onions from drying out as they cook is to add a little water to the pan.

It speeds up the process and deepens that caramelly flavor.

Sautéing vs caramelizing

Sautéing is about softening and lightly flavoring the onions, while caramelizing is about developing a rich, sweet complexity. Unfortunately, you can't swap one out for the other without changing the flavor profile of your dish.

What is the secret to caramelize onions? ›

While you can start the cooking process at medium heat, low and slow is the name of the game when it comes to caramelizing onions. Once your onions begin to soften and take on a golden hue, you'll want to reduce the heat from medium to medium-low or even low for the remainder of the cooking process.

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.

You can use butter, oil or a combination of both to caramelise your onions. Butter adds more flavour than oil, but it does have a tendency to burn.

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.

Cranking up the heat too high.

It may be tempting to crank up the heat to speed the process along, but that's the worst thing you can do; it only puts you more at risk for burning your onions. → Follow this tip: Caramelized onions require time and patience. They're all about low, slow cooking.

You can use either oil or butter to caramelize onions — but ideally, you use a combination of both! I like to use olive oil, and this cooking fat tolerates heat particularly well. Meanwhile, butter adds a distinctly rich flavor to the caramelized onions.