How to Make Caramelized Onions

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Caramelized Onions are easily one of the most deliciously-sweet and versatile things you can make. They are the perfect addition to many dishes, and are often used as a base flavor for things like soups (and of course Slow Cooker French Onion Soup) and casseroles! 

Some of my favorite uses for caramelized onions include caramelized onion dip or caramelized onion pizza (with brie… and balsamic reduction so good right?!)! I find the sweetness from the onions pairs perfectly with a salty or meaty dish! They really take any dish from ordinary to extraordinary!

Close up photo of caramelized onions

How to Caramelize Onions

When you make caramelized onions, they release their sugars which then caramelize, creating a sweet yet savory addition to many dishes such as burgers, steaks, or even soups!

Caramelized onions are not hard to make.  You can cook them in the stove top or in the slow cooker and both are equally delicious! If you cook them in the crock pot, they’ll take about 8 hours but you literally just add the ingredients and walk away!  If you cook them on the stove top they cook much quicker but require attention and stirring.

The real key to amazing caramelized onions is low and slow… like I mean really slow.  Just add some heat, some butter, and some time!

How Long do Caramelized Onions Take?

So many recipes out there claim that you can create perfect caramelized onions in just a few minutes on a stovetop. I wish this was true, but good things take time and these onions are included! I have had the most success with cooking them about 40 -50 minutes.

When you are making them, the key is patience! I find that the slower you cook them down, the more uniform the caramelization process is. Set your burner to low and take your time, you’ll be happy you did!

How do you Caramelize Onions Quickly?

If you need to caramelize onions quickly, adding sugar or a pinch of baking soda (to raise the pH level and help them brown quicker) can help to speed up the caramelization process but truly they aren’t a dish that cooks up quickly. If using baking soda I’d suggest about 1/4 tsp per pound of raw onions.

Caramelized Onions in the slow cooker.

How to Caramelize Onions in the Slow Cooker

The slow cooker has the capability to make perfect caramelized onions without having to babysit a pan for an hour.

To make caramelized onions in the slow cooker, all you have to do is add the onions and butter to the slow cooker, set it to low, and cook them for 8-12 hours! It couldn’t be easier, and the result is a delicious and tender caramelized onion without the hassle of cooking them on a stovetop.

A frying pan filled with caramelized onions

How to Freeze Caramelized Onions

Caramelized onions are a favorite but take a long time to make right. For this reason, I always try to make a little bit extra.

The leftovers can definitely be frozen to add flavor to a weeknight meal that will taste like it’s been cooking all day!

They’ll keep for 4-5 days in the fridge but you can also freeze them to use in soups or casseroles at a later date! I find the easiest way to freeze them is to place them in a freezer bag and press them so they are flattened.  Once frozen, you can break off pieces and add them to your recipe directly from frozen!

I generally label them with the amount of raw onion that was cooked, this allows me to use them as a guide for recipes calling for caramelized onions!

A freezer bag filled with caramelized onions.

5 from 1 vote
Review Recipe

Caramelized Onions

Prep Time 10 minutes
Cook Time 35 minutes
Total Time 45 minutes
Servings 8 servings
Author Holly
Course Side Dish
Cuisine American
Sweet tender caramelized onions are the perfect addition to any dish and the perfect topper to any sandwich!


  • 6 large onions approx. 2lbs, any kind (I prefer white onions)
  • 3 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 1 tablespoon brown sugar optional, see note
  • salt to taste
  • 3 pounds onions sliced
  • 1/2 cup unsalted butter
  • 1/2 teaspoon salt

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  1. In a large non-stick pan, cook onions, butter, olive oil and brown sugar over medium low heat.
  2. Stir frequently until golden and caramelized. (About 45 minutes).
  1. Combine sliced onions, butter and salt (no brown sugar required).
  2. Stir, cover and cook on low 8-10 hours.

Recipe Notes

If you are using sweeter onions (red onions, Walla Walla, vidalia) you will likely not need the brown sugar as they contain enough natural sugars on their own. If using white onions (with yellow-ish papery skin) I would suggest adding brown sugar to help with the caramelization process.
Nutrition Information
Calories: 261, Fat: 17g, Saturated Fat: 10g, Cholesterol: 41mg, Sodium: 158mg, Potassium: 368mg, Carbohydrates: 25g, Fiber: 4g, Sugar: 12g, Protein: 2g, Vitamin A: 9.7%, Vitamin C: 22.7%, Calcium: 6.3%, Iron: 2.9%

(Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.)

Keyword Caramelized Onions

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Caramelized onions are easily one of the most versatile and deliciously-sweet addition to any dish. They go great on burgers, steaks, and even in soups! #spendwithpennies #onions #caramelize #freezerready #easyrecipe
Caramelized onions are easily one of the most versatile and deliciously-sweet addition to any dish. They go great on burgers, steaks, and even in soups! #spendwithpennies #onions #caramelize #freezerready #easyrecipe

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About the author


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Holly is a wine and cheese lover, recipe creator, shopping enthusiast and self appointed foodie. Her greatest passion is creating in the kitchen and making deliciously comforting recipes for the everyday home cook!

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  1. I’m a bit confused. I can purchase yellow onions, that have yellowish paper skins. Once stripped, they are white inside.White onions have white paper skins.

    Do they differ? For this recipe?
    Thanks, Pete

    1. Hi Pete, yellow onions have a sweeter flavor, white onions have a sharper flavor. Both will work for this recipe.

  2. There seems to be a lot of recipes for carmalised onions out there, but all are mostly the same……slow cook onions.

    My two cents : Use Spanish onions, and to that, add an equal amount of red, and orange bell peppers. To that, add a few cloves of crushed garlic, some soy sauce, liquid smoke, salt, some tomato paste, and,,,, mushroom powder. Then slow cook it all down, to a thick paste, ……… it is excellent !

  3. I guess I will try the slow cooker way, so easy to add the ingredients in the slow cooker when preparing dinner, and it will be finished in the next morning. Thank you for sharing!