Learn how to caramelize onions to boost the flavor of main courses, appetizers, soups, stews and more. Caramelized onions are simple to make, can be prepared ahead and stored in the fridge or freezer. Make a batch today and add them to your next weeknight dinner.
The other day my teen asked me, “How do you caramelize onions?” He wanted them for sausage dogs and I was busy, so I sent him to the kitchen with a few tips. After watching him work through the process, I realized a short, clear recipe would be useful — so here it is.
Here’s what you need
Just two simple ingredients for this basic version:
- Brown (yellow) onions
- Olive oil (or butter if you prefer)
Best onions to use
I use brown (yellow) onions for their balanced flavor, but other varieties work well too:
- White onions – mild and higher in sugar; they caramelize nicely.
- Red onions – great if you want a slightly reddish result; good for sandwiches and salads too.
- Sweet onions (like Vidalia) – flatter in shape and naturally sweeter, excellent for caramelizing.
Note: The full recipe and instructions are in the recipe card below.
How to prepare the onions
You can caramelize any amount of onions. I often make a large batch to keep in the fridge. Work in simple steps to save time when preparing many onions.
- Trim the ends – cut off the root and stem ends to make peeling easier.
- Halve the onions – slice them lengthwise to create a flat surface for peeling and slicing.
- Peel – remove the papery outer skin and discard it.
How to slice and cook the onions
- Thinly slice – slice crosswise about 1/8 inch thick. Too thick and the centers stay tough; too thin they may burn.
- Heat the skillet – use a large, heavy-bottomed skillet over high heat. Add the oil and let it warm for a minute. Butter can be used for flavor if desired.
- Start the onions – add all the onions at once and stir well. Let them brown over high heat for 3–4 minutes, stirring occasionally to prevent burning.
- Caramelize slowly – reduce to medium-low heat and continue to cook, stirring every 5 minutes or so, for 30–45 minutes. The onions will slowly release sugars and turn golden brown. If they begin to stick, add a splash of water or stock to deglaze and loosen any browned bits.
Remember: Onions reduce significantly as they cook — expect the finished volume to be roughly one-third of the starting amount.
Perfectly cooked caramelized onions
When finished, the onions should be very soft, sweet and golden brown. They’re incredibly versatile — a staple condiment in my kitchen. Use them in appetizers, on sandwiches and burgers, stirred into sauces, or as an accompaniment to meats and vegetables.
How to store caramelized onions
Caramelized onions keep well and are handy to have ready.
- Fridge: Store in an airtight container for up to five days.
- Freezer: Portion into heavy-duty freezer bags and freeze for up to three months. Thaw in the fridge and reheat gently in a saucepan over medium heat.
Ways to use caramelized onions
These onions add depth and sweetness to countless dishes. A few ideas:
- Sandwiches and burgers: Add to any sandwich, wrap or burger for rich, sweet flavor.
- Charcuterie and appetizers: Serve with cheese and crackers or spoon onto tarts and crostini.
- Main dishes: Mix into stuffed chicken, pasta, or serve with pork and beef.
- Soups, stews and sauces: Stir into marinara, tomato soup or beef stew for extra depth.
Make friends with caramelized onions — they’ll quickly become a go-to in your kitchen. If you have questions, leave a comment in the original post.
I’m back to regular recipe writing for the season and I hope you enjoy these tips. See you soon!
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Get the recipe
How to Caramelize Onions
Ingredients
- 2 lbs onions
- 1/4 cup olive oil
Instructions
- Peel the onions, cut them in half, then thinly slice. Try to slice as evenly and thinly as you can.
- Place a large, deep-sided skillet over high heat. Add the olive oil and heat for about a minute. Add all the onions and stir thoroughly. Brown them over high heat for 3–4 minutes, stirring so they don’t stick or burn.
- Reduce heat to medium-low and stir again. Continue to cook and caramelize the onions for 30–35 minutes, stirring every 5 minutes to prevent sticking and ensure even cooking. If they begin to stick, add a splash of water to the pan.
- The onions are done when they are completely soft and a deep golden brown. Remove from heat.
- Serve immediately or store in an airtight container in the fridge for up to about 5 days. Freeze for up to 3 months.
*Times are estimates; appliances vary.
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