A Step-by-step Guide for Cooking Caramelized Onions

If there’s one thing in life that’s worth the wait, it’s caramelized onions.  They’re easy, therapeutic to make (in my opinion), and absolutely delicious once they’re done cooking.  Here is a step-by-step  guide (with photos!) to help you make your own caramelized onions at home.

step one : pick your onion.

Yellow or white onions are the optimal choice here, as they have a lower water content so they’ll caramelize beautifully and a bit faster than sweet onions.  Sweet onions do contain a higher water content, so they will take longer to caramelize.  Red onions can also be an option, but their higher sugar content can make them more prone to burning, so keep a close eye on them.  So to start, grab a large (go for the biggest one!) yellow or white onion.

step two : prep your onion.

First, cut the ends off of the onion.  

Next, stand the onion up on one flat end, then carefully slice it in half lengthwise.  

See how the onion has subtle lines that run the length of it?  Those are important!  The natural lines of the onion should be vertical as it stands on its end, so you’re slicing with the lines when you cut it in half.  

Once the onion is sliced in half, peel off the crunchy outer shell and the outermost layer.  

Lay the onions, cut side down, onto the cutting board.

step three : slice your onion into half moons.

Cut with the natural lines of the onion, and slice the onions halves into half moons.  Make your onion slices about 1/8 of an inch thick, so they caramelize evenly.

step four : prepare the pan.

Heat a sauté pan with a large surface over medium heat.  (You want as many of the onion slices to touch the heat as possible, to also encourage even caramelization).  Add unsalted butter and olive oil, and allow them to melt and mix together.  A good ratio to follow is one tablespoon of each for every pound of onion.  Wait until the oil and butter are hot before adding the onion slices to the pan.

step five : separate the onion slices, and add them to the pan.

Avoid clumps of onion slices, and separate them with your fingers so they cook evenly.  The best way to do this is by picking up the slices after you cut them, then gently separating them into a large bowl.  That way, you can carefully transfer them to the hot pan.  

step six : coat the onions and add a pinch of salt.

Use a wooden spoon or a wooden spatula to stir the onions around the pan, coating each of the slices in the oil and butter.  Sprinkle a teaspoon of kosher salt over the onion slices, and stir to spread it throughout the onion slices. 

step seven : patience. 

Now we wait. 🙂 Let the onions do their thing over medium heat for at least ten minutes.  After ten minutes is up, gently stir them around the pan, and turn the heat down to medium-low for the remainder of the cooking time.  

From here, stir the onions every ten to fifteen minutes to encourage even caramelization, and keep an eye on their changing color so you can start to recognize the different color and texture as they caramelize.  This entire process should take about 30-40 minutes, and you’ll know the onions are done once they’re very soft and much darker in color!

step eight : the finishing touches.

Almost there!  After about 35-40 minutes, they onions will nearly be done.  Once you get to this stage, add a tablespoon of aged sherry vinegar, and about a half teaspoon of freshly cracked black pepper.  [ PLEASE NOTE : this is entirely optional!  The onions will still be delicious if you do not add sherry vinegar and pepper. ] If you choose to not add these last two ingredients, simply cook the onions for another five minutes until they are deeply golden brown and very soft.

If you DO choose to add sherry vinegar and pepper, stir to coat the onions in both, and allow them to cook for about five more minutes to cook out the acidic flavor of the vinegar.  

Remove the onions from the heat, and allow them to cool for about fifteen minutes before transferring them to an airtight container.  

step nine : eat your caramelized onions on everything. 

Scrambled eggs, tomato soup, grilled cheese, and avocado toast are all awesome vehicles for caramelized onions.  You could also mix them into pastas, toss them into salads, or whatever else sounds good to you!

step ten : store your caramelized onions.

As long as they are in an airtight container in the refrigerator, they will keep for up to four days.  I recommend freezing them though, as they’ll last up to three months this way.  Spoon the onions into an ice tray to create small portions of them, then pop them into the freezer.  Once they’re frozen, pop them out of the ice tray, and transfer them into a plastic freezer bag.  Pop out a cube of frozen onions whenever you need to use them!

I hope this helps you feel comfortable caramelizing your own onions at home!  If you ever have any questions, feel free to reach out to me.  Also, tag me on Instagram if you get the chance to try these out! <3