Well that was the easiest, least-messy batch of caramelized onions I’ve ever made — and I’ve caramelized a lot of onions in my time — on top of the stove, in an oven and on the grill. But I don’t think I’ll bother to do them anywhere but my slow cooker anymore. You have to check this out.
Julienne 6 medium-sized onions. Add them to a crockpot, along with 1/4 cup butter, 1/4 cup olive oil, 3 sprigs of fresh thyme and 2 pinches of salt.
From here, you have the choice of low or high. All of the other recipes I found online cooked the onions on low for 5-18 hours, depending on your crock pot. I wanted caramelized onions for my pizza that night, and our slow cooker’s low is VERY LOW, so I decided to live dangerously.
My onions took 5.5 hours on high and required a little supervision. Try to pile the onions in the centre without too many sticking to the sides of the pot, then stir every hour or two, a little more often towards the end.
If you’re going out for the day, or if you’re cooking them overnight, then set the slow cooker on low — the onions will burn on high unless you stir them occasionally.
And would you look at what you get? The butter really helps develop that deep colour, so unless you need to go vegan, use a 50/50 mixture with olive oil.
Some reviews of other recipes complained about soggy onions, but I didn’t find that at all. If there is too much moisture towards the end of the process, I suggest switching it to high if you’re not there already, and removing the lid for the last hour or so.
Once cool, you can store these babies in the fridge for a couple of weeks. They won’t last that long, though, so I’m not worried about storage. The only question is, how many onions can I fit in my slow cooker? I ‘m going for 10 next time.
How do you use your caramelized onions? Around here, we put them on pizza, in grilled cheese, on roasted chicken sandwiches, in beef stew, and, hypothetically, into a beer & cheese bread that may just save the world. I’ll let you know how that goes next week.



This is super easy! This would be great if you’re planning on making an onion tart, or making a big batch for hot dogs or something. Yum!
Yup — if you need a lot of caramelized onions, this is definitely the way to do it! Theresa
Well, now, THAT’S an idea! Brilliant!
What a great, simple tip. I’m going to give it a try.
Drool! So good! That is a simple yet profound idea. More French Onion Soup for me!
Tamar — I didn`t even think of French Onion soup! I`m sure you could just pour the stock on top of the onions and continue the soup in the slow cooker…Theresa
Caramelizing onions isn’t really my favorite thing but the results area always worth it. I would love to put everything in my slow cooker and let it do the work for me! Thanks for sharing!
That looks really amazing! YUM love the thyme
Note to self: Dust off the slow cooker and use it. Also love the thyme. And use it in omelettes, tarts, steaks, with cheese… with apples…
Claudia — you’ve just put the idea for an apple/onion galette in my head — thanks! Theresa
And I´ve just made a big batch of frikadeller.Onions are a must with them!
How exciting to find this post! I’m definitely going to try this! I make my own “healthy” version of green-bean casserole…using caramelized onions instead of the processed fried ones…and this would make it even easier!!!
I have heard of making caramelized onions in a slow cooker, but have never tried it. I like your tip about cooking it on high without the lid for the last hour. I may have to try this soon!
now isn’t that an easy way to make caramelized onions, and who doesn’t love the sweet taste of those onions…perfect for so many dishes.
Omg – this is SO cool and just made my list of things to do! I can’t wait to see your beer & cheese bread *slurps*
I’m doing the happy dance! I ADORE caramelized onions. I can’t wait to make these because there’s a French onion soup with my name on it once they’re done. Many thanks!
these are the best caramelized onions I`ve ever had — they taste like candy straight from the fridge :)
It’s true — there’s something about caramelizing onions that makes them taste a whole letter better than the long, dreary process on stove! Thank you for this slow cooker recipe — I love the idea that I could just walk away from them (on low, I know!) for hours and they’d be ready when I come back.
We love to put caramelized onions with roasted tomatoes and asiago in grilled sandwiches. The original recipe is from the Ace Bakery in Toronto and it’s possibly my favourite sandwich ever.
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You were absolutely right, you can make them in the crockpot and thank you so much for the inspiration! I wrote a post about it today and you may have just saved me from bringing my crockpot to the thrift store.
long live your crockpot Suzie!
Made these this weekend and froze them. Can’t wait to make pizza from them. Thanks for the great idea!
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Got 9 big onions in my pot right now. I took both of the times and combined them. Cooked on high first three hours then kicked it down to low for four hours. It added two extra hours but I didn’t babysit them during the last hours. Which I was afraid I have to do on high.