Slow Cooker Caramelized Onions
11 Comments Apr 14, 2022
Updated May 28, 2025
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If you love caramelized onions, this slow cooker version is a game-changer—sweet, buttery, and incredibly easy to make. You’ll want to add them to everything.
Caramelized onions usually require constant stovetop attention, but the slow cooker makes it hands-off. Just slice the onions, add a few basics, and let them cook down slowly—no stirring needed. You’ll get the same deep flavor with less work.
Key Ingredients:
These onions are made from scratch, here is what you need. For full recipe amounts, see the recipe card below the images.
- Sweet yellow onions – typically known as Vidalia onions- are the best for frying and caramelizing. They are large onions, have thinner skin, and usually break down fairly quickly, creating a golden brown color when caramelized.
- Butter – melted butter serves as both a cooking oil and flavor booster for this caramelized onions recipe.
- Seasonings – salt and sugar are both used for added delicious flavor. You can use balsamic vinegar if you want a touch of sweetness and a punch of flavor.
How to make Caramelized Onions in a Crockpot
Add sliced sweet onions with butter, salt, and a little sugar, then cook on high. After a few hours, crack the lid to let excess liquid cook off. You’ll end up with rich, golden onions that are perfect your needs.
Variations:
Here are my tips on changing this recipe:
- Olive oil can be used instead of butter.
- Red onions (also known as purple onions) would be the choice in line for caramelizing as they can also be on the sweeter side than other options. Overall, you’ll want to stick with the sweet onions.
- A splash of white or red wine will make the flavor even better.
My Serving Suggestions
Here are great ways to serve these onions:
Barbecued Main Dishes – Slow Cooker Hot dogs, steaks, burgers, grilled chicken, etc. are the perfect meat bases for a caramelized onion topping.
Onion Dip – Make an onion dip. When you caramelize onions, save some for making this yummy dip.
Pasta – adds a deep flavor to any pasta dish.
Soups & Sandwiches – caramelized onions add a fantastic flavor and condiment choice to soups and sandwiches. We often make Slow Cooker French Onion Soup.
Pizza – adding these onions as a pizza topping will take your meal to a new level.
Featured Comment
“This was a nice & easy way to carmelize onions. It took me a longer than 7 hours but I have an old crock pot and it may not have been as hot. I will definitely use this recipe again and freeze batches of onions for the future. We love French Onion soup!”
– Kristie
Slow Cooker Caramelized Onions
Ingredients
- 10 cups sliced sweet yellow onions (1/4 inch thick), 2.5-3lbs. of onions (weighed before peeling).
- 4 Tbsp. salted butter, sliced in pieces or cubed
- 1 tsp. salt
- 1/2 tsp. white sugar, (or use 1 tsp. balsamic vinegar)
Instructions
- (Note this has a 7 hour total cooking time)Peel and slice onions, about ¼ inch thick.
- Place onions in a slow cooker.
- Place the cut butter on top of the onions.
- Sprinkle salt and sugar.
- Cover and cook on High for 5 hours.
- At this point, you will have a lot of liquid in the onions. Stir and set the lid ajar. Cook for 2 more hours on high.
- Serve and Enjoy!
Sarah’s Notes
Nutrition
Nutrition info is auto-generated. This information is an estimate; if you are on a special diet, please use your own calculations.
More Slow Cooker Condiment Recipes
Try Slow Cooker Apple Butter or Slow Cooker Fried Apples for a sweet, cozy side or topping.
Make weeknight dinners easier with Slow Cooker Marinara Sauce or Slow Cooker Spaghetti Sauce—great for pasta or meatballs.
For bold flavor, try Slow Cooker Garlic Confit or a Hot Dog Chili Sauce. And don’t forget Slow Cooker Cranberry Sauce—perfect for holidays or everyday meals.
Hi Sarah!
Happy Easter!
Let me start by saying how much I love your recipes…I use my slow cookers all the time (the one here in AZ because my husband and I have an Internal Medicine/Geriatrics practice, and the one at our 2nd home in PA because when we’re there we are always entertaining, and I like to spend time with my family rather than in the kitchen!)
So, my question about this recipe is, do you ever use a little apple cider vinegar in your caramelized onions? I’ve never made them in a crockpot (always on the stove top,) so I’d like your expert opinion.
I think a touch of apple cider vinegar would be great! I think I will try that next time.
This was a nice & easy way to carmelize onions. It took me a longer than 7 hours but I have an old crock pot and it may not have been as hot. I will definitely use this recipe again and freeze batches of onions for the future. We love French Onion soup!
I’m going to triple this and freeze for so many things Thanks
I have a found a recipe for caramelized onions. it requires you to slow cook them for 24 hours. You also do not add oil or butter to it. It also tells you to use 5 pounds of onions. I’m going to have to make both recipes. Then Compare them
Hi!!! I would love to have your recipe for the 24 hour cook time! Thank you!
Made this yesterday following recipe exactly. It was sooo good. Kept sampling as it cooked so only had one serving left when cooking finished. It was fantastic. Today I trippled recipe so I’ll have enough to actually serve. Just love it.
Trying this recipe tonight – for crock-pot caramelized onions – with a few variations. Only had white onions, so I added a bit more sugar. Used a crockpot liner, and set on LOW for an 8-hour (overnight) cooking time. Wish me luck!
This is similar to how I make my french onion soup recipe: but I place a tea towel over the crock pot before placing the lid. It absorbs lots of moisture. I will have to try your way of leaving the lid ajar. Great recipe
Would this make good french onion soup and do you have a recipe for french onion soup?
You can turn this into french onion soup by adding broth and cooking longer. Here is my french onion soup recipe, though the onions for it are made on the stove top.