Balsamic Caramelized Onions | The Best Caramelized Onions Recipe (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.

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.

No! Onions already contain natural sugars, which is why they're so perfect for caramelizing. This process brings out those sugars to make them more prominent. Adding more sugar would make them too sweet and mess with the flavor.

So using baking soda will speed up the process. But you have to be careful. If you add too much, it will impact the flavor. Different recipes recommend anywhere from ⅛ to ¼ teaspoon per pound of onions (aka about 3 large onions).

The first phase of the process is softening the onions so that they collapse into a tender mass while releasing a good deal of their liquid. 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.

You definitely want the flavor of butter in your onions—but butter has the tendency to burn. For insurance, use a combination of butter and oil, which has a higher smoking point. But how much do you use? Depending on the consistency you want your onions, you can use more or less fat.

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.

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.

If the onions aren't deeply brown after 50 minutes and you'd like to speed things up, you can turn the heat higher to get more caramelization. Stir continuously to prevent burning.

Why did my onions burn and not caramelize? ›

You don't want to slice them too thin or they'll cook too fast which could cause them to burn. You'll also want to start out with fat. I choose oil and butter. Butter gives it a good flavor and helps with the caramelization and the oil helps the butter not to brown too fast.

Cranking up the heat too high.

Caramelizing onions is not an instant gratification process; they take a while to cook. 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.

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.

Using baking soda to caramelize 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.

A large cast iron or steel pan is essential for creating the best caramelized onions. A heavy pan is ideal because it evenly distributes heat and will cook the onions evenly. Even cooking = the best caramelized onions. Nonstick pans don't work quite as well and prolong the process.