How to Caramelize Onions

Caramelized onions are one of the most delicious things you can learn to make. We show you how to caramelize onions that turn out perfect. 

stainless steel frying pan with perfectly caramelized inions and a wooden spatula in it; in background white towel with light green stripe and cutting board with 2 onion halves, onion skin, and chopped onion

Caramelized Onions take a relatively long time to make, but your patience will be rewarded with sweet, jammy onions that are the perfect base for making French onion soup, adding to pasta, or piling onto a burger.

People sometimes confuse sautéed onions and caramelized onions, but when made properly they’re very different. Sautéed onions are cooked quickly over high heat until they’re slightly soft and a pale golden color.

Caramelized onions, on the other hand, are cooked for a longer time over low heat. This allows the natural sugars in the onions to caramelize. The onions will become very soft and jammy and will take on a rich mahogany color.

side by side comparison of sauteed onions and caramelized onions; both in stainless steel frying pans with wooden spatula and cutting baord in background with 2 onion halves on them with chopped onions and a knife

Tips for the best caramelized onions:

  • Slice the onions into strips from root to stem. They might seem bigger than you want at first, but they’ll shrink as they cook.
  • Cover the onions for the first 5 minutes of cook time to bring out some of their moisture. This is called sweating the onions and they won’t take on any color during this step.
  • Next, uncover the onions and sprinkle them with salt. Reduce the heat to low and cook the onions uncovered for 45 minutes to an hour, or until they are evenly browned. 
  • If the onions brown unevenly or a brown coating starts to build up on the bottom of the pan, add a few tablespoons of water and give it a good stir.
  • Some people like to finish their caramelized onions by adding a splash of balsamic vinegar. This helps cut some of the sweetness and adds complexity. I love adding vinegar if I plan to serve the onions with beef.

Should you add sugar?

Some cooks swear by sprinkling sugar over their onions to help them caramelize. This helps develop some color more quickly, but it isn’t necessary.

Properly caramelized onions can’t be rushed but after about 45 minutes they will eventually turn that deep brown color that you’re looking for even if you haven’t added sugar.

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How to Caramelize Onions

caramelized onions in a stainless steel frying pan with a wooden spoon in pan; white and green striped cloth in background; cuttiong board in background with partially chopped onion and knife

Caramelized onions are one of the most delicious things you can learn to make. We show you how to caramelize onions that turn out perfect.

  • Author: Lauren Keating
  • Prep Time: 5 minutes
  • Cook Time: 45 minutes
  • Total Time: 50 minutes
  • Yield: 1 cup

Ingredients

  • 1 Tbsp. oil
  • 2 sweet onions, sliced
  • ½ teaspoon kosher salt

Instructions

  1. Heat a large skillet over medium high heat. Add the oil and the onions.
  2. Cover and cook for 5 minutes, until the onions begin to soften.
  3. Uncover and stir in the salt.
  4. Reduce the heat to low and cook, uncovered, for 45 minutes. Stir the onions frequently to keep them from sticking to the pan. If the onions brown unevenly or a brown coating starts to build up on the pan, stir in a few tablespoons of water.
  5. The onions are done when they are very soft and almost seem melted and are a deep brown color.

How to Caramelize Onions
How to Caramelize Onions

Lauren Keating

Lauren has been cooking for as long as she can remember and shares her recipes at Healthy-Delicious.com, where she features on easy weeknight meals with an emphasis on fresh, seasonal ingredients. She completed the professional plant-based cooking certification from Rouxbe cooking school and enjoys using plant-based cooking techniques to incorporate more fruits, vegetables, and grains into traditional recipes in unique ways. Food-obsessed from a young age, her first words included “cookie” and “eat meat!”