Allow your slow cooker to handle the entire process of creating delicious caramelized onions. For quick access to caramelized onions for soups, burgers, omelets, pizzas, and other dishes, freeze any leftovers.
| Prep Time: | 10 mins |
| Cook Time: | 10 hrs |
| Total Time: | 10 hrs 10 mins |
| Servings: | 16 |
| Yield: | 1 quart |
Ingredients
- ¼ cup melted butter, divided
- 8 onions, thinly sliced
- 1 teaspoon salt
Instructions
- Rub bottom and sides of slow cooker with 1/2 of the butter. Toss onions and salt with remaining butter in a bowl.
- Cook onions on Low until browned and sweet, about 10 hours.
- Substitute butter with olive oil, if desired.
- After 10 hours of cooking, reserved liquid can be strained and used to make soup or sauce.
- Onions can be cooked longer for a deeper brown and more concentrated flavor, if desired. To reduce further, leave the liquid in and cook, stirring occasionally, until the onions are darker brown and the liquid is almost completely cooked off, 4 to 5 hours.
Nutrition Facts
| Calories | 71 kcal |
| Carbohydrate | 11 g |
| Cholesterol | 8 mg |
| Dietary Fiber | 2 g |
| Protein | 1 g |
| Saturated Fat | 2 g |
| Sodium | 170 mg |
| Sugars | 5 g |
| Fat | 3 g |
| Unsaturated Fat | 0 g |
Reviews
I thought these cooked really unevenly so in the end it wasn’t as hands-off as I’d like it to be. Seems to require a good amount of monitoring and stirring, which still might be easier depending on your circumstances, but I don’t see myself using this method again.
I made this recipe years ago using whole sweet onions and one stick of butter. Fill the slow cooker about half full of onions, toss in the butter cube, cover and cook on low heat till onions are dark brown and soft. I wrapped each onion individually and froze in a zip lock freezer bag. I froze the resulting juices in ice cube trays and transferred to another zip lock bag. I threw a cube or two into soups, sauces or gravy that needed that extra special something. Same with the onions. They can be easily sliced or chopped when they are partially thawed. I was afraid the entire house would smell like onions, but it smelled more like beef stew. Heavenly!
I filled my crockpot to the top! Cooked on normal slow cook in my Insta Pot. After 10 hrs still to crunchy for me. Cooked 25 hrs total, turned off at night and back on next day. They took on a beautiful brown color. Make wonderful French onion soup with this. The juice from the onions was a truly rich flavor to add to the soup. Then froze the rest. Will do again!
HINT: I covered my slow cooker pot with several layers of tin foil to make it air-tight so I don’t suffer from onion fumes.
This onion was kinda dry & burners a bit. I’d rather make caramelized onion on stovetop
This recipe I made without the chicken broth and still had plenty of liquid. Do cook another 4 hours to get darker onions and less liquid. My husband used the caramelized onions for everything!!!
This is a good method, but I HIGHLY recommend plugging in your crockpot outdoors if your climate allows . I do mine on a patio table. The smell of cooking onions is way too much to take after a couple of hours.
I made this on the stovetop. Cooked my onions in olive oil and butter combo on medium/high for 10 minutes then added the salt and lowered temp to medium for 40 minutes. Only stirring once every 10/15 minutes. Came out great.
I have made these onion many times. Yes..plug the slow cooker outside and doing them overnight is great. Those not used immediately were put in resealable snack bags in the freezer. I used the bagfuls to put in mashed potatoes, gravies and anything else that would benefit from caramelized onions. Use your imagination!
Wow, love this method. Just slice and throw in slow cooker with butter. I started checking them around 8 hours because I couldn’t believe it could take so long, but 10 hours later and they were perfect — a slight crunch. If you’re not going to use them right away, you want a little crunch because they will cook a little more when you reheat them. If they are mushy, as one reviewer complained, then you likely overcooked them. Every crock pot’s settings are different. I have two crock pots, and low on one of them is medium on another. My daughter recommended adding a little white wine, which I may try next time.
3.5.19 Used the slow cook feature on my 6-quart Instant Pot®, and the uncooked sliced onions just about filled the pot. They cooked on “less” for about 16 hours. I then used the “saute normal” feature on the pot, and cooked down some of the onion liquid, but did reserve some for today’s dinner, French Dip sandwiches. In a word, these onions are DEEE-LICIOUS! Last night, used them on a grilled cheese and bacon sandwich, and over the weekend, they’ll be heading into some French onion soup. I scooped the caramelized onions into the cups of a muffin tin lined with paper cupcake liners, and then put them in the freezer. When they were frozen, I removed them the muffin tin, and transferred them to a gallon-size zip-lock bag. Caramelized onions add such incredible flavor and sweetness to so many dishes, but they do take some time to caramelize, often time you don’t have for a weekday dinner. It is so convenient to already have them on hand, and they can be quickly defrosted in the microwave. If you have a food processor for slicing, this is so very, very simple to make; you just have to allow the slow cooker enough time to work its magic!
Onions turned out great. Doubled the recipe and used my bigger pot on low for 10 hours. Cooked outside on deck so house wouldn’t get smelly.
were a little mushy
Update: 3 lb (not 5 lb) onions yields about 4 cups cooked.
filled my 5 quart cooker with home grown onions and they were delicious! Put them over a roast beef, on a sandwich (heated them in microwave for 30 seconds) and plan on freezing the rest for other things
I loved the smell of the onions…I added thyme and a bay leaf to 3 large sweet onions and 3 small yellow onions. I shouldn’t have added a tsp of sugar as it wasn’t needed. they cooked down and caramelized wonderfully. I will always do this if I have the time. so easy to set and go.
Made to serve with country steak and cubed roasted potatoes at church weekly community café. Was a hit with all partakers. Used onions in ring form. Will probably quarter slice the onions next time. Gave it a four rating
This was the easiest way to make carmelized onions I’ve ever tried. The up side was that they were perfect and tasted fantastic. The down side is that it takes 10 – 14 hours to completely carmelize the onions using the slow cooker. If done for 10 hours, there is a lot of liquid to be drained off for use in another dish (French Onion soup maybe?). If cooked for the additional 4 hours with lid slightly off set, the liquid evaporates and the onions become a deeper caramel color. If you don’t need them right away, this is the way to go as they can be frozen; otherwise they’ll need to be done in the skillet which is definitely quicker but much more labor intensive.
So easy! I put them into the slow cooker the evening before and let them cook all night. The house did really smell in the morning and for a long time afterwards, but if you put out a bowl of vinegar on your counter it quickly absorbs the residual smell. I used regular yellow cooking onions and didn’t add any sugar, which worked great! I have made this a few times and I prefer to make large batches and then freeze them in a few different portion sizes for later use. I don’t plan to ever go back to the stove top method!
Great and easy to make. I used them in the slow cooker french onion soup recipe on this site. Started the evening before hitting the sack and in the a.m. added the rest for the soup. I would suggest adding a little sugar depending on the type of onions you use. Mine were the ordinary yellow onions
Instead of straining off the liquid (and onion sugars), just cook with the lid off on high, stirring occasionally. I made these to go with some collards (which needed that extra sweetness from the onion to counter the bitterness of the greens). Worked beautifully!