Caramelized Onion In The Slow Cooker Or Crock Pot

Prep Time
Cook Time
10h 15m
Ready In

"I got this recipe from a girlfriends which she had passed down to her from her grandmother who originally did it in a cast iron pot/pan and in a slow oven but my girlfriend adapted it for the slow cooker. Since cooking this recipe using my 1.5 litre crock pot and just a little over 3/4 full of sliced onion I found mine was well caramelised at the 9 hour mark and very little liquid, so I turned off at that point. I have made this quite a bit since last posting using a different crock pot/slow cooker (I have 5 and one of those has 3 different size inserts) and this time I did it in my smallest one (1 litre) and it took 8 1/2 hours to get it to the point that I like it to be. So far the timing have varied between 6 to 10 hours depending on the sized and I always filled to about 3/4 full but by the time they had caramelized, they only took up about a 1/4 of the pot. Last night I served some of the onions in a hot dog roll a beef sausage."

Original is 15 servings


  • Serving Size: 1 (42.9 g)
  • Calories 39.9
  • Total Fat - 2.7 g
  • Saturated Fat - 0.4 g
  • Cholesterol - 0 mg
  • Sodium - 79.2 mg
  • Total Carbohydrate - 3.7 g
  • Dietary Fiber - 0.7 g
  • Sugars - 1.7 g
  • Protein - 0.4 g
  • Calcium - 9.3 mg
  • Iron - 0.1 mg
  • Vitamin C - 3 mg
  • Thiamin - 0 mg

Step by Step Method

Step 1

Peel and thinly slice all of the onion into half moons and transfer all the onions to the slow cooker/crock Pot (4 - 6 quart size) and it should be half to three-quarters full.

Step 2

Drizzle the olive oil or melted butter and then add the salt over the top of the onions and toss to evenly coat all the onions with a thin glaze of oil or melted butter.

Step 3

Cover the slow cooker/crock pot and cook for 10 hours on low.

Step 4

If you are around while the onions are cooking, stir them occasionally as this will help them cook more evenly, but isn't strictly necessary.

Step 5

After 10 hours, the onions will be golden-brown and soft, and they will have released a lot of liquid, so if you like them as they are now, stop cooking and pack them up once they have cooled down.

Step 6

If you'd like jammier, more concentrated onions with a deeper colour, continue to cooking for another 3 to 5 hours on low and leave the lid ajar so the liquid can evaporate, check every hour and stop cooking whenever the onions look and taste good to you.

Step 7

Remove the onions with a slotted spoon and transfer them to refrigerator or freezer in containers.

Step 8

If any liquid remains in the slow cooker, crock pot, transfer the liquid to a separate container and this can be used as cooking broth in another recipe.

Step 9

Onions keep in the refrigerator for 1 week and in the freezer for at least 3 months.


No special items needed.

1 Reviews


Yum. These are so simple and good. Since I was making them for myself, I filled up my 1-quart slow cooker and they turned out really well. Thanks for sharing this great keeper, Pat.


review by:
(26 Sep 2019)

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