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How to make caramelized onions in the slow cooker (recipe)

Slow cooker caramelized onions. #slowcooker #crockpot

The seductive aroma of onions cooking all day perfumes every corner of my house, yet I'm not lifting a finger. No standing at the stove with a wooden spoon, no turning the flame down, down, down to make sure nothing is burning. Caramelizing brings out the natural sugar in onions, resulting in a condiment you can use in everything from soup to scrambled eggs, in a panini or on top of pizza. If you've ever wondered how to make caramelized onions in the slow cooker, or whether it's even possible, I'm here to tell you that you can, and you must, because nothing could be easier. Use regular yellow onions, not Vidalia or other sweet onions that contain more water. I trim five pounds ($1.99) of ordinary yellow onions down to a bit less than four pounds, slice them in the food processor, and cook them for 9 hours. I've been putting caramelized onions in everything lately, and I'll share a couple of the ways I use them later this week. A batch of onions will keep in the refrigerator for a few weeks. You won't be able to resist their allure.

Use your slow cooker to make caramelized onions! #slowcooker #crockpot

How to make caramelized onions in the slow cooker

From the pantry, you'll need: onions, olive oil, cooking spray.

Makes 4 cups.


5 lbs yellow onions, peeled and trimmed
Cooking spray (I use olive oil cooking spray)
2-3 Tbsp olive oil


Spray the ceramic insert of a 4- or 5-quart slow cooker with cooking spray.

Thinly slice the onions (a food processor makes quick work of this), and pile the onions into the slow cooker. Drizzle with 2-3 tablespoons of olive oil, and stir with a rubber spatula. The cooker will seem impossibly full, but that's fine.

Cover and cook on HIGH for 8 hours, stirring 2 or 3 times if you happen to be at home. The onions will reduce to fill less than a third of the cooker, and will turn golden brown and soft. Then, uncover the cooker, and continue to cook on HIGH for 1 hour, to allow some of the liquid to evaporate.

Remove the cooked onions from the slow cooker with a slotted spoon, let cool, and pack into containers with tight-fitting lids. Refrigerate for up to 2 weeks.

[Printer-friendly recipe.]

More recipes in The Perfect Pantry:
Kale, mushroom and caramelized onion breakfast casserole
Clam, bacon and caramelized onion pita pizza
Lemon onion hummus
Whole wheat pizza with pumpkin, black beans and caramelized onions
Brown rice and almond pilaf

Other recipes that use these pantry ingredients:
Braised short rib sandwich with caramelized onion marmalade, from Pinch My Salt
Broccoli rabe with caramelized onions, from Simply Recipes
Warm green lentil salad with caramelized onions, feta cheese and pears, from Andrea Meyers
Horseradish meatloaf with caramelized onions and sour cream-horseradish sauce, from Kalyn's Kitchen
Mujadara (rice, lentils and caramelized onion pilaf), from Herbivoracious

It's so easy to make caramelized onions in the crockpot!

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I MUST try this! Such a great way to use the slow cooker.

Great synopsis on why we love carmelized onions! I have made them like this in the slow cooker for years, although sometimes use butter instead of olive oil. Also a splash of good balsamic vinegar (sometimes more than a splash) can bring out a wonderful flavor, too.

Thanks for this post! I think I'll make some this week...


Kalyn, I've been putting in a lot of time with the slow cooker over the past few weeks, and of all the things I've made, this has to be the most satisfying.

Robin, I thought I might have to add some balsamic but the flavor was so good without it. And I like keeping the onions as "generic" as possible, so I can use them in many different ways. I wish I'd tried this years ago!

OH MY!! Now THIS has to be the best slow cooker tip yet! Caramelized onion, roast beef and goat cheese spread on ciabatta sandwiches are in my future!

Oooh, how tantalizing, Lydia! I just made roasted veggies this week and used some sweet onions in the mix. They were caramelized in the process. The flavors were incredible! I wonder how sweet onions would work versus yellow onions. I have so many right now. I had planned to use them in a recipe I was developing, but life has been too busy for me to get to that yet and I need to use these onions. I think I'll give them a try in this recipe, Lydia. I might sautee some mushrooms in a skillet (so they release their liquid) and throw them in close to the end, too. Hubby would flip over that topping combo for a good steak! ;-)

Thanks, dear!

Carol, my next post here is something very similar to what you describe, so stay tuned!

Shirley, my understanding is that the sweet onions have a lot higher water content than the regular yellow onions, so you have to watch out that the onions don't actually steam in their own liquid. I'm guessing that cooking the onions uncovered for longer than one hour might help evaporate the excess liquid.

What a fantastic idea! I love caramelized onions, but hate tending them at the stove. I'm pulling out the slow cooker next weekend!

TW, dust off that slow cooker! I've been using mine a lot lately, so there are more recipes to come. This one, though, is one you'll want to make often. Having caramelized onions on hand in the fridge has really changed the way I cook.

Oh yum - one of my favorite foods made easy! I love them, but not the long tending that is required stove top.

Genius. The only concern I have is eating the whole thing, in one sitting, by myself!

Mary, this is one of my favorite uses for the slow cooker! As a person who likes to improvise in the kitchen, you're going to love having these onions on hand.

Pattypro, same here. They are good enough to eat with a spoon, right from the container!

I'm a slow cooker fanatic - I use mine at least a couple of times a week - but I never thought of that.

Have just started a load 10 minutes ago. Thank you.

Do you know how (or if) these would freeze? I can see putting these in a tart or quiche...I'm practically drooling here! Getting ready to slice my onions NOW!

Love this, can't wait to try it!

Pat, these onions will change your life! Well, they'll change your cooking. It's so easy to make a batch, and budget-friendly, too.

Jessica, I think you could freeze these, but I haven't tried it. Please let us know if you do, and how it works out.

Absolutely incredible I can not understand why I didn't think of this;-)

It works!

Lydia, these are such a favorite. I've gotten into the habit of freezing them in 5 oz. portions, (not sure how I came up with that amount!). If a recipe calls for chopped onions, I just run my chef's knife through them and proceed from there.

Patty, ever since I started making my onions this way, I've never gone back to stove top. (5-ounce portions? I'll have to try that!)

Get a really nice start to caramelizing the onions on the stove top or in a slower cooker. Microwave the sliced onions until they are about half the volume before throwing them in your slow cooker or pan. It gives them a head start and cuts the cooking time down substantially.

Sipagolda, thanks! Great tip.

Look what Joy just posted: http://joythebaker.com/2012/05/french-onion-soup-sandwiches/
I only have two portions left in the freezer, so you just know what's happening...soon!

any comments on making these into french onion soup?

Elithea, I do it all the time. Go for it!

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