Curious how to make caramelized onions? It’s not hard! Three ingredients are all you need to make this simple condiment that takes any meal up a notch. Caramelized onions make a great addition to sandwiches (especially grilled cheeses), salads, omelettes or frittatas, and more.
Do you think there’s a savory dish out there that wouldn’t be improved by the addition of caramelized onions? I gave that question a little thought and couldn’t think of anything off the top of my head. Soft and richly coated, it’s amazing what two incredibly basic ingredients and forty-five minutes can do to a raw onion.
While I’m a frequent caramelized onion eater, writing a post on how to make caramelized onions wasn’t on my mind until recently. It’s a pretty basic procedure after all, but its versatility makes it a kitchen MVP. It’s well worth having as a recipe on its own and adding to the cooking + baking How-To section with other staples like roasted garlic, baked tortilla strips, and cold brew coffee.
How to make caramelized onions: the #1 tip!
The name of the game when it comes to making caramelized onions is low and slow. Thin onion slices are stirred with melted butter and a pinch of salt over very low heat. It may not seem like much is happening at first, but over time the onions will soften greatly and begin to turn golden.
How golden is good enough? Well, that’s kind of up to you. I like to cook the caramelized onions until they’re a nice golden brown without any burnt or very well done bits, but you can certainly keep them going until you’re happy.
The first step is slice each onion in half from top to bottom (through the ends), trim off the top end, and then make two small notches around the bottom stem piece to remove it.
Then, with the notched-out section at the bottom (so, facing you), slice the onion very thinly. The picture below shows what just one onion produced, though you’ll be doing this for both. Once the onions are sliced, you may wish to go through the pieces and separate out any slices that have stuck together.
Even though you’re ideally using a large pan (mine seen here is 10” with tall sides, but a 12″ pan would be even better.), you may think you have too many onion slices to fit in there comfortably. As the onions will reduce in size, I add them to the pan in batches, stirring the onions up as they slowly reduce.
Once a little room opens up, add more onions to the pan. It takes about three or so batches for me to get all of the onions in there. It’ll look crowded, but it won’t be for too long.
Give everything a nice seasoning of salt, and then lower the heat. You don’t need to measure. I usually add a several hefty turns of my salt mill.
As the caramelized onions cook, they’ll slowly become softer and more pliable, but won’t begin to turn golden right away. That’s okay! Low and slow is what we want.
As time goes on, you’ll notice the onions continue reducing in size. Keep periodically giving them a stir and keep an eye on them as the time reaches twenty, twenty-five minutes.
(Though every stove top has its own idiosyncrasies and your caramelized onions may cook a little faster or slower.)
Your mileage may vary, but for me it takes about forty-five minutes for the onions to reach the wonderfully jammy caramelization you see in the photo below. That’s the time between lowering the heat once all the onions are in the pan to the golden color you see here.
It’s crazy how much they reduce! Two huge onions worth of slices result in approximately three-quarters of a cup of caramelized onions in total.
- Don’t be scared of how large the pile of onion slices is in comparison to the size of your pan. They reduce considerably while cooking.
- This caramelized onion recipe will yield approximately 3/4 cup of onions. Estimating about 2 tbsp per serving, it’ll result in about 6 servings.
How to Make Caramelized Onions
- 2 large yellow onions
- 2 tbsp unsalted butter
- Salt, to taste
- Slice each onion in half from top to bottom, through the ends. Slice off the very top part of the stem. Make two small "v" shaped cuts around the root to remove it from each onion half.
- With each onion half aligned with the "v" cut facing you, slice onions lengthwise into very thin slices. Run your hands through the pile of slices to make sure they're all broken up and separated.
- Add butter to a large pan set over medium heat. Once the butter is melted, add about one-third of the sliced onions to the pan (or enough to cover the surface area of the pan) and stir slices into the butter. Let cook for 2-3 minutes, or until the onions have reduced slightly and more room opens up in the pan. Add another batch of onions to fill it up again, stirring and waiting a few minutes for them to reduce.
- Continue until all of the onions are in the pan. This took 3 batches, with a total of 8 minutes between starting with the first batch and adding the last. Season with salt to taste.
- Reduce heat to low. Periodically stir onions as they reduce and eventually become golden in color. It took about 45 minutes for the onions to reach the golden color you see in the final pan picture here, but cook them until you're satisfied with the coloring. Store unused portions in the refrigerator.