Caramelised Onion Relish | Community Recipes | Nigella's Recipes (2024)

FAQs

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.

Use Water. Like I mentioned above, we want to get rid of all the water in the onions to allow for browning to take place. But once the onions do start to brown, water can be your best friend! Adding water periodically into the pan while caramelizing your onions will prevent burning.

Cooking instructions

Caramelize the onions: Heat about 1 tablespoon of canola oil in a large skillet or dutch oven over medium-low heat. Once hot, add the onions and stir to coat. Let cook, stirring every 5-10 minutes, until deeply caramelized, about 1 ½ - 2 hours.

You'll see some people add sugar to the recipe, which is done to speed it up. Doing this is caramelising the sugar, not the onion. The onions get plenty sweet enough on their own if you take your time with it. From a health perspective it's much better not to add extra sugar.

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.

Tip: use apple cider vinegar for white and yellow onions and balsamic vinegar for red onions. Tip: the vinegar serves to deglaze the pan, adds acidity, and brings this recipe together by boosting the tangy and savory flavors of the caramelized onions. If the onions stick to the pan, that's fine.

If you cover the pan, you'll trap steam, which will speed up their softening, heat them more quickly, and help release their liquid more quickly. Lift the lid a few times during this stage to give them a stir and make sure nothing is browning yet.

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.

When you add baking soda during cooking it changes the pH which increases the Maillard reaction causing the onions to brown more quickly. The higher pH also causes the onions to soften more quickly, which we cover below when we discuss the texture.

The best type of pan for caramelizing onions is a wide, thick-bottomed cast iron or stainless steel pan. Although onions can also be caramelized with alternative cooking methods and containers, like a crock pot or slow cooker, nothing beats a sturdy sauté pan.

Why won't onions caramelize? ›

Cook onions too little, and they won't have enough time to develop that sweetness; cook them too hot and those sugars can burn.

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.

Use ⅛ teaspoon of baking soda mixed with 1 tablespoon of cold water per 2 to 3 pounds of onions. Stir it in at the end of cooking for about 1 minute. Adding it too early will break down the onion fibers, turning them into mush.

Around 30 Minutes: Onions should be light blonde in color and starting to become jammy. More fond is starting to build up, but it should still be fairly easy to scrape it up with the evaporating liquid from the onions. Around 40 Minutes: Onions are golden and starting to smell very caramelized.

Stirring the onions and scraping down the sides of the pan often to ensure no strand darkens faster than another is key. A heatproof rubber spatula is the tool for this job; it's stiff enough to scrape the bottom of the pan and flexible enough to clean the sides.

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.