Slow Cooker Caramelized Onions

I’ve gotta say I’ve wanted to try crockpot caramelized onions for a long time…and I finally have. I have mixed feelings about my crockpot, btw. What they do well, they do SO well and what they don’t do well…yikes!

Caramelized Onions in the Crockpot
Caramelized Onions in the Crockpot

I have a few mixed feelings about the onions done in the crockpot, too. The final result was pretty darned good but there were a few that stuck to the sides of the pan and burned a bit, even though I stirred several times. You can’t just keep opening the lid over and over with a crockpot.

Admittedly, they weren’t too bitter and since I wasn’t using my onions until the next day I tossed them in the fridge – as I reheated I noticed that they all kind of magically had evened out in color. You can see some darkness in the photos here & there, though.

The other bothersome thing was the smell! Seriously, the onions I’ve caramelized stove top or in the oven didn’t smell like the ones in the crockpot do, and it didn’t go on for hours and hours, either!

The biggest drawback is that it’s really hard to judge when the onions will be done – at least the first time. I’d recommend starting them before you go to bed on a day you’ll  be around in the a.m. so you can keep a pretty close eye on them as they finish.

All crockpots are a bit different, so you’ll want to figure out the timing for yours. Could be 8 hours or up to 12. Figure it out the first time (and if you’re like me, write it down) and it will be easier to get close to the mark for future batches.

When I cooked these, I had no leftover onion juice by the time the onions were caramelized to my liking. This might vary by the crockpot and the onions. If it appears there is too much juice, lift the lid of the crockpot and allow to evaporate.

On the plus side, it was so low maintenance I’d do it all again!

Caramelized Onions in the Crockpot
Caramelized Onions in the Crockpot

Caramelized Onions in the Crockpot

  • Servings: abt 3 cups
  • Difficulty: easy
  • Print

  • 3 pounds onions, sliced about 3/8″ thick
  • 2 tablespoons butter
  • 2 tablespoons olive oil
  • 1/2 teaspoon salt

Melt butter, toss olive oil, butter, salt and onions together. Add to crockpot and cook on low for 8 hours (or more) or on high for 6 hours (or more.) Stir two to three times during the process.

Store in the fridge for several days or the freezer for several months.

Note: Length of time depends on the crockpot and how deeply caramelized you wish the onions to be. Watch carefully during the final hours to prevent burning and to determine the timing for the next batch you make.

from the kitchen of


You know I’ll be bringing this to our Throwback Thursday #29 Link Party, hosted by Quinn of Dad What’s for Dinner, Meaghan of 4 Sons are Us, Alli of Tornadough, Carlee from Cooking with Carlee and Moi! That’s right – me!

Click over to our Throwback Thursday post for links to their blogs and social media, rules and more info or just click on the blue leapfrog, below, to view all the Throwback Thursday Posts or enter your own!

I’ll also be bringing this recipe to Fiesta Friday 111 hosted by Angie and cohosted this week by Naina @ Spice in the City and Julianna @ Foodie On Board, as well as Freedom Fridays, What’s Cooking Wednesdays & Weekend Potluck.

39 thoughts on “Slow Cooker Caramelized Onions”

    1. Kyla, the first time i used my StepMom’s old round crockpot and I made them last week with my newer model. It needed a bit more babysitting at the end. Just thought I’d toss out that hint!

      1. I was thinking about whether I would be able to do them in my crockpot. I have a really huge one that needs to be at least half full when it’s operated. That would be a LOT of onions! I might just try a mini batch in my Little Dipper. Otherwise, I’ll have to borrow my mother’s smaller crockpot 🙂

          1. How big are your crock pots? I can’t remember if mine is 8 quarts or 10, but it’s one of those really huge ones that you could cook a turkey in.

      1. Oh my gosh, what a great idea Molly! Our house gets so danged hot in the summer and we cook a LOT on our deck with our propane grill and gas burner out there. But who said you couldn’t put a slow cooker on the deck too? 😀

        1. I was just thinking about the story of my dog (he was a used dog) that his former owner told me. They let him out early Thanksgiving day and when they opened the deck door, he had someone’s ham! lol!

  1. I love that you can do a whole mess of onions while you are doing them in the slow cooker. They do have a few drawbacks, but it is worth it! I’m going to have to check out that bolognese sauce.

  2. I’ve never heard of doing this in a slow cooker Molly! They turned out perfectly. I think this would be pretty good for me as last time I tried to caramelize onions I never quite got there. I got too tired part way through (and I ended up with crispy-and-burnt onions instead…).

    1. I don’t know about you but I get tired standing at the stove and get distracted sometimes when I leave it…so this was nice b’coz it doesn’t really need a lot of attention. I did mention that the color was a lot more haphazard when I first took them out of the crockpot and stuck them in the fridge. When I pulled it back out and reheated the did kind of meld into gorgeous color…

    1. Well, it’s mostly just sitting around waiting for the onions in the crockpot. Much faster stovetop but more hands on stirring. I do have to say it was worth all the patience!! 🙂

  3. I’ve been curious about caramelizing onions in the crockpot. Though I love the smell and taste of onions, I don’t think I want to wake up to the smell or have the house smell like onions all day. The low maintenance is a big draw and your finished onions look good, so I might still try this on a day I can keep the windows open! 🙂

    1. That might be a bit prudent! 🙂 It’s funny when i caramelize them with other methods, the smell is so different – here it was very strong. At any rate, I think I’ll have onion soup (and caramelized onions for other things) a lot more often with this recipe – frankly my energy level isn’t always real high so a lot less stirring and babysitting suits me fine…

  4. I don’t have a slow cooker but I’ve made great caramelized onions in a dutch oven. And it lasts for ages in a jar in my fridge for addition to various dishes. Speaking of … I have some perogies (with caramelized onions and potatoes in the filling) in the freezer that are made even better pan fried in some butter/olive oil and caramelized onions and a spoonful of sour cream on top.

      1. When you’re only cooking for one, a batch is enough for 4 servings. I still have one left in the freezer. If I had sour cream in the house, I’d boil them up but I’m house bound (car is in for repairs).

  5. we are just started learning the slow cooker – as you said, some things are good and some things are not. I like the idea of caramelized onions in the slow cooker – will have to try it!

    1. I hope you do – I’d love to hear what you think about them! By the way, I was somewhat emboldened after these onions and decided to make a crockpot dinner yesterday that we saw in a magazine! It was a glum dinner…we forced it down and I had to endure comments like “It’s not so bad, really…” lol! I might just stick to my pot roast, stew and bolognese sauce. Now that’s a great recipe!! You might really like it!

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