Easy Slow Cooker Caramelized Onions recipe that is ready in 5 hours. This quick 4 ingredient recipe is the best and will make your mouth water!

Too many onions? Make Caramelized Onions!
These Slow Cooker Caramelized Onions came at a perfect time since we just planted our onion seeds for Spring, and I was able to use the remaining 3 pounds of last years onions for this recipe. It’s always magical when the timing works out perfect and you can go from harvest to seed without much waiting in between.
These onions (and fried onions!) are what dreams are made out of. By slow cooking them we’re bringing out the natural sweetness of the onions as the sugar caramelizes. What starts as a full Crock-Pot of onions is going to turn into a much smaller amount as they melt down.
What you’re left with (besides an amazing smelling house that is going to make your neighbors jealous) is savory, sweet onions that are ready for you to add anywhere – soups, casseroles, sandwiches, salads, pasta, pizza – seriously, you can add them to anything! Just throw them in your mouth already!
Ingredients
The ingredients are simple because this recipe is simple!
- 3 pounds onions – peeled and sliced
- 1/2 cup butter – melted
- Salt
- Sugar
How To Make Caramelized Onions
This recipe calls for 3 pounds of sliced onions. I use my 6 quart Slow Cooker and the onions take up about 75% of the space when they begin. Peeling and slicing 3 pounds of onions is tough business so if you have sensitive eyes like me I suggest wearing sunglasses while doing this.
- Add all of the ingredients into a large slow cooker and stir so the butter coats the onions.
- Cook on high for 5-6 hours or until the onions are soft. For me this usually takes 5 minutes.
- Serve with your favorite dish or freeze the onions for later. That’s it. Easy, right?
Matthew came home and he started to immediately swoon upon the first smell of these sweet onions. On the first bite, his knees buckled and I had to catch him! People will fall in love with these onions!
Not only do I love the results of this recipe but I love how easy it is to make too! This recipe will be for sure one that will stick around with us for years to come after we pick our garden onions. I hope you give them a taste – I think you’ll be really happy you did!
FAQ
How many cups of onions does this make once the onions melt down?
Approximately 2-3 cups.
Can I freeze THESE?
Yes! Caramelized Onions freezes amazing! I use my Ball silicone trays or WeeSprout containers to freeze them – this makes it easy to pop one or two cubes out at a time. Alternatively, you could freeze in ice cube trays. Just make sure to pop them out of the ice cube trays if they don’t have lids once frozen and transfer to freezer safe bag.
What are the best onions to caramelize?
Yellow onions tend to be sweeter so they’re best for caramelizing. We grow “candy” yellow onions in the garden which in my opinion have perfect sweetness.
How Can I use Caramelized Onions?
Soups, casseroles, grilled cheese sandwiches, salads, meats, pasta, pizza and more – seriously, you can add them to almost anything!
How do you store onions to make them last longer?
Use pantyhose to store onions (seriously) or these bags (I recommend them in size XL) – ours keep for about 8 months this way
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Slow Cooker Caramelized Onions
PrintIngredients
- 3 pounds onions peeled and sliced
- 1/2 cup melted butter
- 1 teaspoon salt
- 1 teaspoon sugar
Instructions
- Add everything into a large slow cooker and stir so the butter coats the onions completely.
- Cook on high for 5-6 hours or until they are soft and caramelized. My slow cooker usually takes 5 hours.
- Serve with your favorite dish or freeze for later.
Matthew says
We have too many onions and this is a great way to save them for later.
Steve Warren says
The secret to tear free onion slicing is a very sharp knife.
I start with a small serrated edged paring knife to top and tail the onions,
then placing a now flat end on the cutting board, I slice the onion in half with a thin bladed small japanese cleaver – which I also use to slice the onions.
Next I slip my thumb under the outer layer of the onion (inside the brown skin which may slip off anyway) and pry this layer off and discard it because it is often tough, sometimes a bit green and cooking doesn’t usually compensate for that.
Then I place the onion half flat side down and slice away with the very sharp knife – and hardly ever get teary eyed. Well, not from cutting onions anyway!
Pamela says
Hey Steve, thanks for sharing your tips!
Nisha @ Honey What's Cooking says
OMG ,these look insanely good! Just wow.
[email protected] says
This is genius! You have changed the way I will caramelize my onions forever!
Cheyanne @ No Spoon Necessary says
I have a serious obsession with caramelized onions. Like, I will make VATS of the stuff, because i want to be able to eat it by serving spoon full and still have enough left over to use it in actual dishes. But, I’ve never tried making it in the slow cooker! For some reason I didn’t think it would turn out well, but obviously it does because yours looks amazing!!! SOOOO DOING THIS! Cheers, girl!
Anu - My Ginger Garlic Kitchen says
Caramelized onions in a slow cooker for real? This sounds like a genius idea. Would love to try this recipe.
Amy (Savory Moments) says
This is a terrific idea! It would be perfect for making all the onions for French onion soup ahead of time.
[email protected]'s Recipes says
Didn’t even know that you can make caramelized onions in slow cooker…so cool! Definitely give this a try.
Sues says
Oh yum!! I’ve never thought to caramelize onions in my slow cooker, but this is such an awesome idea!! I bet my kitchen would smell soooo delicious 🙂
Kayle (The Cooking Actress) says
ooooh I love caramelized onions too–my knees would probably also buckle 😛