How To Caramelize Onions

How To Caramelize Onions

Do you ever find yourself craving the sweet, savory unctuousness of caramelized onions?  I do.  Part of it is their versatility — I use them in everything from breakfast frittatas to casseroles or as the crowning glory on a dish of haricots vert.  But if I’m honest, it’s the flavor — that slightly honeyed jamminess in every spoonful that makes me want more and if you’ve never made them before, here’s a simple guide on How To Caramelize Onions.

Yellow onions.

First, you’ll need some onions (I used 5-pounds for this batch).  Standard yellow onions are best.  Save your vidalias, white onions and red for your burgers or pico de gallo.

Sliced yellow onions.

Slice the onions into quarter-inch rounds.

Onions in the slow cooker.

Heat a large heavy bottomed pot with a lid (I prefer a dutch oven) over medium heat with a little olive oil and add the onions.  Toss the onions in the oil to coat and cook for about five minutes.  You don’t want to brown the onions, so adjust your heat if it seems too hot.  Sprinkle with a little salt, cover tightly and slowly sweat the onions.

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Cooking the yellow onions.

Witness the metamorphosis.  It’s nothing short of amazing.   This process isn’t difficult or labor intensive – you just have to be on hand for stirring the veg and monitoring the pot for hot spots — adjusting the heat when necessary.  

Slow cooking onions.

Now, I’ve seen recipes for this with a “set it and forget it” mantra. “Slow-cooker” caramelized onions and “cooked in the oven” options, but I have doubts about the level of real caramelizing that goes on.  I mean, sure — they’ll soften and reduce down.  They’ll even give up their liquid.  

caramelized onions on a wooden spoon.

But, in my humble opinion, to achieve the Maillard reaction that transforms these eye-stinging rings into the golden hued, barely held together, strands of mild sweetness that I’m looking for, requires two things.  A sturdy dutch oven and patience.  

Closeup of Caramelized Onions

You’re efforts will be rewarded with this satisfying, ready-for-anything condiment.

Finished caramelized onions.

They are great on top of a juicy burger or tossed with blanched green beans as a special side dish.   Caramelized onions are delicious with a roast chicken and they’re mandatory for salisbury steak!


To save yourself some time at the last minute, make a large batch of onions and then freeze them in 1/4 or 1/2 cup containers, that way, you’ve always got them on hand when the mood strikes.

Closeup of caramelized onions.

Recipes to use caramelized onions in:

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How To Caramelize Onions
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5 from 4 votes

How To Caramelize Onions

Always keep caramelized onions on hand by making them in large batches and freezing in 1/4 cup or 1/2 cup containers.
Author: Lisa Lotts
Course Side Dish
Cuisine American
Keyword onions
Dietary Restrictions Dairy-Free, Egg Free, Gluten-Free, keto, Low-Carb, Paleo, Vegan
Prep Time 10 minutes
Cook Time 2 hours
Total Time 2 hours 10 minutes
Servings 8


  • 1 5-pound bag yellow onions
  • 3 tablespoons olive oil
  • ½ teaspoon kosher salt
  • special equipment: large dutch oven with a tight fitting lid


  • Peel and thinly slice the onions. (save the roots and peels for making vegetable stock).
  • Heat the dutch oven over medium heat and add the olive oil. Add the onions and cook gently, stirring for about 5 minutes to separate the rings of the onion and get them coated in the oil.
  • Sprinkle on the salt and stir to combine. The salt will draw out the moisture in the onions. Cover with lid and reduce heat to medium low to continue cooking.
  • Stir the pot every 15-20 minutes to assure that nothing is sticking to the bottom. If you see the onions browning — the pan is too hot and you should reduce the heat. You want the onions to slump over the course of cooking. When they’ve given up all of their liquid, only then do they start to caramelize. Don’t confuse “brown” with “caramel”.
  • Continue cooking until the liquid has evaporated and the onions take on a deep golden hue. The onions should be so tender that they almost fall apart and should be sweet.
  • The cooking time will vary on the pot your using and the stove. Just keep checking on it regularly, stirring when necessary and not letting it stick to the bottom of the pot.
  • 5 pounds of onions reduces to about 2 cups of caramelized onions. If you’re not using it all at once, portion out and freeze the remainder in small containers until ready to use.


Calories: 46kcal | Fat: 5g | Sodium: 145mg

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This easy recipe gives step by step instructions on How To Caramelize Onions and different ways to use them! They're sweet and delicious - naturally vegan and gluten free!

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  1. I’m making these for french dip sandwiches. Is there a point in the recipe where you remove the lid, or do you leave it on the whole time?

    1. You’ll remove the lid to stir the onions, but it should be kept on for most of the time.

  2. Rita Chapman says:

    I would like to use these onions with garlic to add to steamed cabbage and carrots. I am making this recipe for 100 people.

    1. That’s a lot of people! You should be able to use garlic… but I would add it after the onions start to soften. You’ll need boatloads of onions for that many folks!

  3. I’ve tried to caramelize onions once before but it was a disaster. Thanks to your recipe, this task seems so manageable! Does this goes only for yellow onions or I can use also white ones?

    1. I’ve never done it with white onions, but I don’t see why it wouldn’t work with them as well. You could probably use red onions as well.

  4. 5 stars
    Learning how to properly caramelize onions was a game changer for me in the kitchen. I love to do it on fall days. And you’re right – low and slow is best! I’ve honestly never frozen them before. Do they retain their yumminess?

    1. They absolutely do! I’ve found little quarter cup plastic containers that I use for freezing. It’s just the right amount of onions for a few omelettes or burgers or whatever…

  5. 5 stars
    I do love the rich flavors that are pulled from caramelized onions. They can make a simple dish absolutely fabulous. I have never made them in advance and frozen them, hadn’t even thought about it… great idea.

  6. This looks mouthwatering! I have the Dutch oven and can get the onions, just need the patience. I can’t wait to make these. Maybe tonight! What a great idea to make them ahead of time and freeze.