Put your slow cooker to work to cook onions! All you need is onions, a little butter, a slow cooker and some hands-off time.
Caramelizing onions in a slow cooker is the best way to get golden, buttery onions. A few years ago I read that you can cook onions down in a slow cooker. I tried it once and it was a complete failure. I wanted to make French onion soup so I wanted to try again. This time it was a major success.

If you’ve ever had caramelized onions, you know how absolutely amazing they are. But making them on the stovetop takes a really long time and a whole lot of babysitting.
Whenever I make my homemade chip dip, I need caramelized onions, and standing there waiting for them to slowly cook is a pain. The slow cooker makes easy work of caramelizing onions for any recipe.
You can use any amount of onions you like. This recipe used a 3-pound bag of yellow onions. Be careful if you buy a bag at the store. I bought a bag “fresh” and the onions had definitely seen better days.
Slice up the entire bag of onions somewhat thin. A mandoline or a food processor will make this process quicker. Plus you will get nice and even slices.
Put the onions in a large slow cooker. You’ll want a 5 or 6-quart slow cooker depending on how many onions you are cooking. Next, add the butter, olive, and some salt and set the slow cooker to low.
Now, many recipes say you can walk away for 12 hours and have perfectly cooked onions. But if your slow cooker runs a little hot, or it’s not filled up 2/3 of the way for optimal cooking, you will need to stir the onions every hour or so for at least the first 3 hours. You may still get a few burned onions, but not enough for it to be a problem.
After 12 hours of cooking, the onions should be a nice dark brown caramel color. And your house probably smells amazing, too!
So now what? Store the onions in the refrigerator or freeze them for later to make French onion soup or yummy potato chip dip!
How to Cook Onions in A Slow Cooker
The Easy Way to Cook Onions in A Slow Cooker
Slow cook a large batch of caramelized onions in your Crock Pot slow cooker!
Ingredients
- 3 lbs onions, sliced
- 2 Tablespoons butter
- 2 Tablespoons olive oil
- 1 teaspoon salt
Instructions
- Put the sliced onions in a 5 or 6 quart slow cooker. Add the butter, oil and salt and stir the onions a little. Put the top on the slow cooker and cook on low for 12 hours.
- Stir the onions every few hours or so to make sure they don't burn.