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. With just a few ingredients (onions, butter and olive oil) and a bit of time you can easily make perfectly sweet and golden onions!

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 and of course perfect for topping Hamburgers!

Caramelized Onions in a frying pan

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!

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 your favorite soup recipes!

What kind of Onions to use for Caramelized Onions? I find sweet onions work the best but you can truly use any kind of onion to caramelize.

You can cook them on the stove top or in the slow cooker and both are equally delicious!

The real key to amazing caramelized onions is low and slow.  Just add some heat, some butter, and lots of time!

How Long do Caramelized Onions Take?

If you cook them in the crock pot, they’ll take about 8 hours. 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.

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!

Onions are full of sugars so cooking them at a high temp can cause them to burn. I have had the most success with cooking them about 40 -50 minutes. The slower you cook them down, the more uniform the caramelization process is. Set your burner to low and take your time.

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 a crockpot

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, add the onions and butter to the slow cooker, set it to low, and cook 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.

caramelized onions in pan

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 extra.

The leftovers can 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 can also be frozen to use in casseroles at a later date! The easiest way to freeze is to place in a freezer bag and press until flattened.  Once frozen, break off pieces and add them to your recipe directly!

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!

Onions in a bag for How to make Caramelized Onions

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caramelized onions in pan
5 from 7 votes
Review Recipe

Caramelized Onions

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

Ingredients

  • 6 large onions approx. 2 pounds, any kind (I prefer white onions)
  • 3 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • ½ tablespoon brown sugar optional, see note
  • salt to taste
Or Slow Cooker Caramelized Onions
  • 3 pounds onions sliced
  • ½ cup unsalted butter
  • ½ teaspoon salt

Follow Spend with Pennies on Pinterest

Instructions

Stovetop
  • In a large non-stick pan, cook onions, butter, olive oil and brown sugar over medium low heat.
  • Stir frequently until golden and caramelized. (About 45 minutes).
Slow Cooker
  • Combine sliced onions, butter and salt (no brown sugar required).
  • 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, Carbohydrates: 25g, Protein: 2g, Fat: 17g, Saturated Fat: 10g, Cholesterol: 41mg, Sodium: 158mg, Potassium: 368mg, Fiber: 4g, Sugar: 12g, Vitamin A: 485IU, Vitamin C: 18.7mg, Calcium: 63mg, Iron: 0.5mg

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

Keyword Caramelized Onions
Course Side Dish
Cuisine American
Onions in a pan with a title for How to Make Caramelized Onions
Onions in a pan with writing for How to Make Caramelized Onions
caramelized onions in a skillet with a wooden spatula

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Holly

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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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Comments

  1. Holly, up your website and recipes are my go to for any new recipes.thank you for this. I will be home more regularly for awhile and will be finding up yummy dishes to make for my family.5 stars

  2. I can never seem to get my onions to caramelize to the nice golden brown color no matter how low and slow I cook them. I have given up in frustration. They get nice and tender but not caramelized. I have tried with and without sugar (white not brown) as my friend carmalizes it with no sugar. I have used both white and yellow onions. Any suggestions on what I should do? I only have “teflon” style non stick pans.

    Any help appreciated!

    1. I would suggest trying the slow cooker method. It makes a large batch of onions and they can be portioned and frozen for future use too.

  3. 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.

  4. 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 !

  5. 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!5 stars

  6. Holly,
    Can you make them in an Instant Pot? Saute’ them first and then pressure cook them?

    Thank you for responding :)