This slow cooker caramelized onions recipe is perfect if you want to make some caramelized onions in bulk. It’s so easy to get prepared and cooking quickly.

Slow Cooker Caramelized Onions

The onions will cook to have a lovely deep brown color and have flavors that will leave you wanting caramelized onions on everything. This method of preparing caramelized onions is so incredibly simple it’s a surprise more people don’t do it.

Making caramelized onions at home is a great way to save on money. Store-bought varieties will often set you back five or more dollars. However, the ingredients in this recipe should only set you back a few bucks.

You can store the caramelized onion in a glass jar for later. It will keep in the fridge for about a week, maybe longer. If you want it to last longer, then you can seal the jar or simply freeze for later.

Caramelized Onions

There are so many uses for caramelized onions that it’s impossible to list them all. Just a few of examples include having it as a topping on pizza, in a toasted cheese sandwich, or even in a delicious homemade dip.

You can even use the caramelized onion as a replacement to onion in dishes such as slow-cooked soups, pies and so much more.

If a video is your preference, then you can find one right below. You can find the full written recipe to the slow cooker caramelized onions underneath the video.

Slow Cooker Caramelized Onions Recipe

Prep time
15 Minutes
Cook time
12 Hours
Total time
12 Hours & 15 Minutes


  • 1kg (2.2 lb) onions, sliced
  • 30g (1 oz) unsalted butter
  • 1 tbsp. balsamic vinegar
  • 2 tbsp. brown sugar


  1. In a slow cooker, add the onions and scatter the cubed butter over the top.
  2. Scatter the brown sugar and the balsamic vinegar over the top.
  3. Cook on low for 8 hours.
  4. Leave the lid slightly ajar and cook for a further 4 hours. The liquid should evaporate and become thick and jammy.
  5. Serve & Enjoy

Cooking Tips

  • Don’t stress too much on the thickness of the slices of onion. The long cooking time will ensure that all the onion will be cooked over the course of a few hours.
  • You can leave the balsamic vinegar and the brown sugar out of the recipe, but the caramelized onions will not be as flavorsome.
  • If the onions don’t appear to be cooking fast enough, then you can turn the heat up to high. This heat increase will dramatically reduce the cooking time of these onions.
  • This dish will produce a strong onion smell, so if you're not a fan of onion make sure you have the slow cooker cooking under a ventilation fan.
  • Freeze the caramelized onion in ice cube trays. This method is great if you only ever need a serving of caramelized onion at a time.
Get the latest recipes delivered to your inbox.

Nutritional Information

All the nutritional information for some slow cooker caramelized onions is right below. It has all the information that you need to know.

Please keep in mind that this information is just an estimate as I made use of an online tool to calculate it.

Nutrition Facts
Serving Size: 134g (4.73 oz)
Servings Per Recipe: 8
Amount Per Serving
Calories 70 Calories from Fat 19.8
% Daily Value*
Total Fat 2.2g 3%
Saturated Fat 1.3g 7%
Trans Fat 0g
Cholesterol 4mg 1%
Sodium 7mg 0%
Total Carbohydrate 12g 4%
Dietary Fiber 2g 8%
Sugars 6g
Protein 2g 4%
*Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

There are plenty of other condiments that you can make in the slow cooker. The apple butter is certainly another condiment that is well worth making. It’s especially useful if you need to feed a crowd.

I hope that this slow cooker caramelized onion recipe is an absolute hit with your friends and family. If you have any feedback regarding this recipe, then be sure to leave a comment below.

Note: I use a 5.5L (6 Quart) slow cooker for all the recipes that I have on this website unless specified. If you have a smaller or larger slow cooker, then you might need to adjust the ingredients.