How to make slow cooker caramelized onions

by Emily from Frugal Living NW on July 20, 2014

Slow Cooker Caramelized Onions

Apparently, I am on a caramelizing kick. First, this Salted Caramel Pear Apple Butter. Then butternut squash. Last week was Roasted Garlic. Now caramelized onions. Somebody stop me! The ingredient list is so short, the steps so simple, and the results so good that it’s hard not to be a fan. Just like with roasting garlic, caramelizing onions replaces that often sharp, bitter bite with a sweeter, deeper flavor. These mellow onions can be used in anything from soups and stews to pizzas and burgers. Or just spread some goat cheese over a slice of bread and lay some caramelized onions on top. I did. Then I ate it for breakfast. I’m not pregnant or anthing, but boy, did that taste good. For this crock pot method, you only need two ingredients: onions and butter. 1/2 cup (one stick) of butter may seem a bit over the top, but once you drain and chill the onions, that onion-infused butter will harden on the surface of the cooking liquid. Use it to saute vegetables or add it to other dishes. If you own a larger slow cooker, you can also double the amount of the onions without increasing the amount of butter. I’ve also read recipes using olive oil, if you’d prefer that route. I’ve made caramelized onions a handful of times, but this is the first time I’ve ever used my slow cooker. Starting it before I went to bed one night last week, I must’ve woken up four different times to the fragrant smell of sweet onions filling the house. It was like a beautiful dream, with a little elf named Crockpot cooking up something tasty in my kitchen all night. If you’re not a big fan of the smell of onions, maybe set your slow cooker on the back deck? You can achieve more perfectly caramelized onions stirring them in a pan on the stovetop, but this method will give you good results with very little effort.

Crockpot Caramelized Onions

From Slow Cooker Cooking (Amazon) Yield: about 3.5 cups


3 lbs. onions, peeled and cut into 1/8-1/4″ thick slices 1/2 c. (1 stick) butter salt (optional)

    1. Put the onions and butter in a slow cooker and cover with the lid.


  • Cook on low for 12-14 hours, until the onions are deep brown and very soft. It’s almost impossible to overcook these.



Eat right away. Fridge or freeze for later. Visit Frugal Living NW’s profile on Pinterest.

Looking for the perfect slow cooker for this and other appetizer-sized recipes?

Check out the Crock-Pot 3-Quart Round Manual Stainless Steel Slow Cooker. No matter the recipe or the occasion, your Crock-Pot Slow Cooker keeps the temperature steady so your food is cooked to perfection, full of flavor and delicious. To keep clean up easy, the 3-quart removable round stoneware slides right out of the base for easy transport to the table or storage in the fridge. And both the stoneware and lid are dishwasher-safe. Amazon has this item in stock and ready to ship!

This post may contain affiliate links. See the disclosure policy for more information.

{ 5 comments… read them below or add one }

Jenn July 22, 2014 at 9:01 am

Any pointers on freezing these bad boys? Freezer bag or mason jar? I love these on burgers and yes, of course, French Onion soup!!


Emily from Frugal Living NW July 22, 2014 at 9:58 pm

I use a freezer bag and spread them flat before pushing the air out of the bag. With such a thin layer, it’s easy to break off just as much as I want.


mrule February 24, 2013 at 12:29 pm

I had a disappointing experience with this. The onions turned straight-up grey and smell like onion sewage.


Nichele October 27, 2012 at 4:20 pm

I’m going to say you made me go out and buy 10#’s of onions just to try this recipe out. Not kidding either. I wanted to make more french onion soup but have been very busy so just didn’t do it. Now that I can do the onions like this I’m off to make soup and can it. Found a great recipe and everyone loves it. Thanks for this one. Love your site.


Jaz November 8, 2012 at 3:23 pm

Ha I was thinking french onion soup too! Which will work nicely with my kitchen torch to toast the bread


Leave a Comment

Previous post:

Next post: