Caramelised onions are a favourite here and the absolute best way to make them is in your slow cooker. The long cook time ensures perfectly caramelised onions without adding any sugar and it's basically hands-off cooking. These are most definitely the best caramelised onions you will ever make!
Why you're going to love this recipe
Once you've chopped the onions you can set and forget, knowing that your onions are caramelising! Here is why you're going to love these slow cooker caramelised onions:
- dairy free
- gluten free
- refined sugar free
- set and forget cooking
- no need to stand and stir for ages at the stove
- naturally caramelised, with only 3 ingredients
- caramelisation brings out their sweetness and turns onions from a savoury vegetable to a sweet delicious condiment
- making them in bulk saves time!
Bulk or batch cooking things like this saves you so much time! Realistically, if you did one onion it would take 12 hours using this method, so doing ten saves you time!
What goes into the recipe
don't forget to scroll to the recipe card for amounts and full method
Could it be simpler?
- onions- I use ten! Brown, purple, white it doesn't matter! They just have to be sliced into rings
- olive oil- one tablespoon per onion.
- salt- 1 teaspoon per 5 onions, add more if you want, but they are best when not super salty.
How to make this recipe
- First you need to slice up your onions. The quickest way to do so is to use your food processor. It also saves the tears! (Image 1)
- Combine the onions, olive oil and salt in your slow cooker. Mix well. (Image 2)
- Turn on for 12 hours on low. Stir when you can. (Image 3)
- Freeze flat on a tray and then store in a container. (Image below)
Slow cooker tips
Your slow cooker is your best friend! I use mine year round. For this recipe we are using it on low for 12 hours. I normally make this recipe in a 6.5 litre cuisinart, but this time I tried it InstaPot on slow cooker mode because it hasn't left the bench since I bought it.
I think they actually work better in the InstantPot. And the stainless steel bowl means the next meal you cook doesn't taste like caramelised onions. Which is a bonus!
My slow cooker fits ten onions. If yours doesn't, adjust the recipe down. You need 1 tbsp olive oil per onion and 1 teaspoon salt per 5 onions.
Expert Tips and FAQs
It doesn't matter, brown, white or even purple work perfectly, and a combination of them is great too!
It's all about long, slow cooking, which does the caramelising for you. As they cook long and slow in the slow cooker, the onions release their natural sugars and brown.
Time! And flavour. While fried onions have a purpose, they are just savoury and not exciting. When onions are caramelised, they become sweeter and are more delicious!
Not at all! Especially when made with no added sugar. Despite tasting super sweet, they aren't bad for you at all. By using minimal salt and healthy olive oil, these onions taste delicious. Onions themselves contain no fat and are a good source of fibre.
Onions will be dark and soft, much darker than golden when they are caramelised. You can see from the finished photos how dark they will be.
I freeze them until solid on a large tray and then I cut into portions. Otherwise you can freeze them in baby food pods, or ice cube trays.
More slow cooker recipes
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Slowcooker Caramelised Onions
- 10 brown onions sliced thinly to make rings- you can do this in about 3 minutes in a food processor or you can use a mandoline or by hand with a sharp knife and a firm grip.
- 10 tablespoons of olive oil
- 2 teaspoons sea salt
- Put all the onion rings in the slow cooker and mix the olive oil through.
- Sprinkle the salt on top and give it another stir.
- Pop the lid on the slow cooker and turn it to low for 12 hours.
- I tend to give them a stir every couple of hours.
- Check them after 12 hours.
- They may need more time.
This post was the first ever post on my blog, published on 26/09/2014. It has been completely updated on 14/07/2021 to include process shots, step by step video and FAQs.