How to Make Caramelized Onions - The Recipe Critic (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.

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.

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.

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.

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).

Depending on the consistency you want your onions, you can use more or less fat. Just cover the bottom of your pan for jammy, soft caramelized onions, or add a little more for more structured, slightly charred caramelized onions. The more fat in the pan, the more the onions will fry rather than soften.

Yes, you should cover the onions when caramelizing them. Covering the onions helps to trap the steam and heat, which aids in the caramelization process by softening the onions and allowing them to release their natural sugars. This results in a sweet and flavorful caramelized onion.

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.

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.

Why did my caramelized onions turn to mush? ›

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.

I love non-stick pans for making pancakes and eggs, but they're not the best pick for caramelized onions. Instead, I recommend using a cast-iron skillet. As the onions cook, a delicious fond will develop on the bottom of the pan. If you scrape it up and stir it into the onions, it will make their flavor even richer.

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.

You don't need the balsamic vinegar, which is only there to add some flavour. The caramelization — the browning of the sugar in the onions — will take place just fine without the vinegar. Absolutely! You only need oil or butter or a bit of each in a frying pan.

A few reasons could be that you sliced them too thick or too thin. You haven't cooked them long enough. Your heat isn't at the right temp, use between medium and medium-low. Adding too many onions at once can actually cause them to steam because of too much moisture, instead of caramelizing.

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.

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.

Instructions. Heat the oil in a large skillet over medium-high heat. Add the onions, peppers, salt and pepper. Reduce the heat to medium-low and cook, stirring frequently, until the onions are caramelized and the peppers are tender and slightly browned, 15 to 20 minutes.