How to Caramelize Onions for Burgers, Hot Dogs and Beyond

editor@purewow.com (PureWow)

Complex and naturally sweet, caramelized onions have the ability to balance salty and sour flavors and they make for a beautiful accent to almost any meal...when done right, that is. Unfortunately, one wrong move and your glazed, golden masterpiece will turn into a burned and bitter disappointment. Not to worry: We got the scoop on how to caramelize onions, so you’ll be able to cook them beautifully every time.

How to Caramelize Sliced Onions on the Stove

Prep time: 10 minutes; Cook time: 20 minutes

Caramelized onions take patience and a watchful eye—but when done right, the payoff is well worth the work. Here’s a foolproof breakdown of what to do so you can taste the sweet fruits (or roots) of your labor.

1. Peel and Prep

Remove the skin from the onions before cutting them in half through the root end. Then start slicing them up lengthwise into ¼ to ⅛ inch slices. Keep in mind that a thinner slice will be quicker to caramelize, but much easier to burn—so watch your onion accordingly.

2. Ready the Skillet

Heat a cast iron pan or skillet over medium heat and add 1-2 tablespoons of butter—an especially good choice given that the heat isn’t too high and butter is delicious—or any oil of your choosing.

3. Sauté and Stir

When the oil begins to shimmer, toss the onions in the pan one handful at a time—adding more slices as soon as the last bunch begins to soften. Once all the onion slices have been added to the skillet, continue cooking them over medium heat while stirring frequently. Seriously, don’t abandon your post: Cast iron pans are particularly prone to developing hot spots, and you don’t want any single onion slice sitting in one for too long.

4. Watch and Wait

Keep a close eye on the onions—easy enough because you’re still stirring pretty often—and lower the heat immediately if you see (or smell) them beginning to burn. As for cooking time, the National Onion Association says that stovetop caramelization can be achieved in roughly 20 minutes—but you’ll know for sure that you’ve made delicious onion candy when it takes on a rich, golden hue.

5. Add Finishing Touches

At this point, your onions are ready to serve, but feel free to continue the caramelizing action for another 5 minutes for an even deeper, sweeter flavor—just taste as you go to ensure the onion doesn’t get bitter. (Actually, you can keep caramelizing for even longer, but you might need to add a splash of water to prevent the onion from sticking to the pan.) Once you’ve crossed the finish line, serve up your yummy reward with basically anything...but more on that below. 

How to Caramelize Whole Onions on the Stove

Prep time: 5 minutes; Cook time: about 20 minutes

Don’t relish the idea of slicing six onions? We don’t blame you. Luckily, you don’t have to. Joe Brancaccio (chef and owner of Brancaccio’s Food Shop) suggests you roast small cipollini onions whole on the stove for a deliciously caramelized treat with minimal prep work involved. Brancaccio prefers this method because the whole roasted onions deliver maximum sweetness and a melt-in-your-mouth texture. Here’s how to do it.

1. Prep the Onions

Trim a bit off each end of the cipollini onion and peel away the tough outer layers. Place the peeled onions in a bowl and toss them with 1 tablespoon of olive oil and a splash of balsamic vinegar, if desired. (Note: Balsamic vinegar will enhance the sweet caramelized flavor, but the chef says it’s optional because all onions have natural sugars which means they don’t need any help to do their thing.)

2. Start Caramelizing

In a skillet, heat 1 tablespoon of olive oil. Continue cooking the onions over medium heat, lowering the flame if necessary to prevent burning. Stir and turn the onions occasionally and cook until golden brown on all sides. “I don’t do ‘how long?’” says Brancaccio, adding that one of the benefits of stovetop roasting is that it's easier to tell when they are done. So what do you look for? “The ideal example is a small onion with a caramelized outside and soft inside.” Prod a golden-brown cipollini with a fork at around the 20-minute mark—if it’s soft to the touch, it’s ready to serve.

How to Use Caramelized Onions

Caramelized onions are incredibly versatile—serve them up as an elegant side dish or incorporate them into a recipe as a tasty counterpart to other ingredients. You’re welcome to snack on your deliciously caramelized onions straight out of the pan, but be sure to reserve some for one of the following recipes for maximum enjoyment.

RELATED: How to Make Pickled Onions, Because They Taste Good on Everything