Caramelized Onions heaped up in a cast iron skillet

How to Make Caramelized Onions

An easy guide to making caramelized onions.  Plus a pro tip you'll laugh at!  Calories listed are for 1 cup of caramelized onions. 

Course Side Dish
Cuisine American
Keyword How to Make Caramelized Onions
Prep Time 5 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 35 minutes
Servings 3 cups
Calories 225 kcal
Author With Two Spoons


  • 3 pounds yellow onions
  • 1 Tablespoon olive oil
  • 1/4 teaspoon kosher salt


  1. Peel onions.  Using the root as an anchor, slice into rings.  (Wearing swim goggles during this process can make this a far more comfortable process.)

  2. Heat olive oil over high heat in a large dutch oven or cast iron skillet until it shimmers.

  3. Add onions and stir to coat.  Turn down heat to medium.  Add the kosher salt.  The key is low and slow.  

  4. Cook onions for approximately 1 hour, stirring every 10 minutes or so. (Resist the temptation to stir too frequently.  The onions need to be in constant contact with the bottom of the dutch oven in order to begin the Maillard reaction).

  5. Cook for an additional 30 minutes or so, stirring more frequently as the onions begin to brown.  Scrape the bottom of the dutch oven (or cast iron skillet) as you stir.  You are done when all of the onions are soft and browned.

Recipe Notes

3 pounds of onions will yield 3 cups of caramelized onions.

Plan on patience as these onions turn out the best when you cook them slowly, over low heat.

Perfect recipe to make on a lazy Sunday afternoon.

Any caramelized onions you don't plan on using within 3 days should be frozen-I use quart sized freezer bags to freeze 1 cup portions.  Perfect caramelized onions ready for your next recipe!