How to Make Caramelized Onions

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Caramelized onions add a whole lot of flavor with very few ingredients and even less effort, so long as you know the secrets. Here’s how to caramelize onions.

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The Best Caramelized Onions Recipe

Chopped onion is the foundation to oh-so many recipes. But as everyone knows, raw and sometimes even sautéed onions can be intense or overpowering.

But when sliced onions are cooked low and slow in a bit of butter and oil, they become savory bites of sweet candy that are nearly jam-like, transforming everything from burgers to pizza to pastas, and definitely chips in dips, with their deep, rich, and nutty sweetness.

Don’t even get me started on soup. French Onion Soup without caramelized onions would simply be tepid broth, and who’s craving that?

Caramelized Onions Ingredients

It’s not necessarily the ingredients that make caramelized onions a success, it’s time and patience. Low and slow is the name of this caramelized onion game. Like all simple recipes, the fewer the ingredients, the more important it is to do it right because there’s no cover to mask mistakes.

To make this caramelized onion recipe, all you need is:

Butter
Canola oil
Onions
Kosher salt
Fresh thyme
White balsamic vinegar (optional)

How to Caramelize Onions

Slice the onions in half from stem to stem, then slice into half moons. You’ll have a whole lot of onion at the start, but as it cooks, those onions melt down considerably.

I use a cast iron skillet or a heavy bottom skillet so the onions deepen and darken and create little bits of fond (the buttery sugar remnants) on the bottom of the pan that are periodically stirred into the whole goodness.

Mom, Are We There Yet? How Long Does It Take to Cook Caramelized Onions?

You want the onions to cook slowly to release their sugars and caramelize, stirring just every so often so the onions become bronzedand jammy. Sure, this process takes time—at least one hour over medium-low heat—but this isn’t a dish you have to sit and babysit the entire time. In fact allowing the onions to gel together without stirring deepens their flavor.

The onions are done once they’ve reached their bronzed beauty look. I feel they’re a success when I have deep and dark strands entwined with lighter plump strands holding all that onion essence. Once you’ve made these a few times you’ll discover your favorite way too.

Short On Time? How to Caramelize Onions Quickly

If your craving doesn’t jive with the hands on the clock and those onions need to be done in a hurry, take this shortcut route. They’re not quite as good as the low and slow method, but they’ll do in a pinch.

What Are the Best Onions for Caramelized Onions?

I typically use yellow onions for this recipe, but sweet Maui onions and even red onions each work well too.

Can I Use Regular Salt Instead of Kosher?

Yes, but you’ll need to add less salt than the caramelized onion recipe calls for. Table salt has smaller grains than kosher salt, so if you added the full teaspoon the recipe calls for your caramelized onions would wind up tasting far too salty.

Tips for Making the Best Caramelized Onions

Be sure to slice the onions quite thinly. If the onions are too thick, they won’t caramelize properly.

Also note that you can’t use dried thyme in this recipe, only fresh. Fresh thyme is less potent than dried and will soften up as it cooks.

If the onions look like they’re on the verge of burning or get dry, add a little water or stock to loosen them and rehydrate. Some recipes suggest adding a splash of vinegar to brighten the process, and sometimes I do and sometimes I don’t. It’s your call.

More Caramelized Onion Recipes You’ll Love

Homemade French Onion Dip
Sweet Potato and Caramelized Onion Pizza
Bacon Double Cheddar Cheeseburger with Caramelized Onions
The Best French Onion Soup
Chorizo and Caramelized Onion Dip

If you make this recipe, please let me know! Bookmark this recipe and leave a comment below, or take a photo andtag me onInstagramwith #foodiecrusheats.

4.60 from 37 votes

Caramelized onions add a whole lot of flavor with very few ingredients and even less effort, so long as you know the secrets. Here's how to caramelize onions.

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Course Snack

Cuisine American

Keyword onions

Prep Time 5 minutes minutes

Cook Time 1 hour hour

Total Time 1 hour hour 5 minutes minutes

Servings 1 ¾ to 2 cups

Calories 522kcal

Ingredients

2 tablespoons butter
1 tablespoon canola oil
3 large yellow onions , peeled, halved and thinly sliced
1 teaspoon kosher salt
3 sprigs fresh thyme (leaves only)
1 tablespoon white balsamic vinegar (optional)

Instructions

Melt the butter with the canola oil in a large cast iron or heavy bottomed skillet over medium high heat.
Add the onions and sprinkle with the kosher salt and fresh thyme leaves. Cook the onions for 5 minutes or until they start to soften, stirring so they don't crisp or brown in spots.
Reduce the heat to medium-low, cover with a lid, and continue to cook, stirring the onions every 10-15 minutes or so. The onions will reduce and become more golden and jammy as they cook, giving off a rich nutty aroma. If the onions look like they're beginning to burn or crisp, stir in a splash of water or broth and scrape the caramelized fond from the bottom of the pan for the onions to absorb. Add the vinegar if desired in the last 10 minutes of cooking.
Continue to cook up to 1 hour or so for a deep, rich caramelized flavor. Serve immediately or refrigerate for up to one week.

Notes

Caramelized onions take time for the flavor to develop but not a whole lot of hand-holding. Allow the onions to cook undisturbed in between stirring times for the caramelization to happen naturally.

Nutrition

Recipes That Are Even Better With Caramelized Onions

French Onion Grilled Cheese Sandwich
Porter Caramelized Onion Dip
French Onion Cheese Bread
Heirloom Tomato, Zucchini, Caramelized Onion and Feta Galette

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How to Make Caramelized Onions | foodiecrush.com (2024)

FAQs

Do you use oil or butter to caramelize onions? ›

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.

Keep Reading ›

Do you need to add sugar to caramelize onions? ›

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.

Know More ›

What makes onions caramelize faster? ›

So adding water and covering the skillet causes the raw onions to wilt faster and more evenly as the water turns to steam. Then, uncover the skillet and begin a process of pressing the softened onions into the bottom and sides of the skillet for maximum contact—and maximum browning.

Learn More ›

Should you salt onions before caramelizing? ›

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.

Explore More ›

How long does it take to caramelize onions properly? ›

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.

Discover More ›

Why can't I get my onions to caramelize? ›

Adding too many onions at once can actually cause them to steam because of too much moisture, instead of caramelizing. Not enough heat, the maillard reactions is a complex chemical process but simply put its the reaction of reducing sugars and protein impacted by heat.

Keep Reading ›

Which onion is best for caramelizing? ›

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.

What is the secret to browning onions? ›

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.

Learn More Now ›

Does covering onions help them caramelize? ›

You don't have to cover the pan if you don't want to, it merely shaves some minutes off the total cooking time.