Crockpot Caramelized Onions (Paleo, AIP, GAPS, Wahls, Whole30)

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bowl or caramelized onions with some whole raw onions alongside in comparison

“Banish the onion from the kitchen and the pleasure flies with it. Its presence lends color and enchantment to the most modest dish; its absence reduces the rarest delicacy to hopeless insipidity, and dinner to despair.”
~ Elizabeth Robbins Pennell

Making It Easy

If you’ve ever made caramelized onions the traditional way, you know they take almost an hour in a skillet over low heat, stirring occasionally. While this is an opportunity for cooking meditation, it can be challenging for the impatient among us! That’s where this recipe is a godsend. Just pop the onions in your crockpot in the evening and walk away. In the morning, your house will smell amazing and you’ll have enough caramelized onions to store and use at a moment’s notice.


In honor of Dr. Terry Wahls , I love celebrating the nutritional power of vegetables. Look how your body benefits when you incorporate onions into your diet:

  • Prebiotics: You’ve heard of probiotics, but do you know what prebiotics are? Mark Sisson calls them “food for our flora.” They feed the beneficial bacteria in our digestive tract, which is vital to nutritional healing. Onions are a potent prebiotic food.
  • Antioxidants: Onions are high in polyphenols and flavanoids, which are antioxidants that support our health in a myriad of ways. As long as they are cooked over low heat, these nutrients remain in the onion.
  • Detox: Dr. Wahls lists onions under the category of sulfur-rich vegetables, which support our bodies’ natural detoxification pathways, another important component of a healing diet.
  • Research has shown that onions are a potent anti-inflammatory, can increase bone density, and even have cancer-prevention benefits.
  • Vitamins: Onions are also a decent source of Vitamin C, B6, Folate, Potassium and Manganese.
  • Carbs: They are also a good source of carbohydrates, which can come in handy when you’re on a grain-free diet and find yourself accidentally eating too low-carb for your health.
  • Varieties: All onions are good for you, but here’s an important fact: sharp onions have 5 times more antioxidants than sweet onions. They also caramelize better, so choose them for the recipe below.

adapted from Shockingly Delicious

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Crockpot Caramelized Onions

Crockpot Caramelized Onions (Paleo, AIP, GAPS, Wahls, Whole30)

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  • Author: Eileen Laird
  • Total Time: 10 hours 10 minutes
  • Yield: 3 cups



  1. Peel onions, slice thinly, and toss in the crockpot.
  2. Drizzle oil over the top. Use two spoons to toss until evenly coated.
  3. Cover and cook on LOW for 10-12 hours, until onions caramelize. They reduce greatly in size, become a deep brown color, and develop a sweet and intense flavor. 
  4. This recipe makes 3 cups. They’ll last in the fridge 1 week or in the freezer 6 months.


  1. Uses: They're delicious by themselves as a side dish. They also taste great on top of burgers, steak, or liver. You can add them as a topping for a grain-free pizza, sandwich or wrap. They're also delicious sautéed with your favorite vegetables. Anywhere you add them, they'll bring a rich burst of flavor.
  2. Note: I don't recommend using an Instant Pot as your slow cooker for this recipe. While Instant Pots do have a slow cook function, they're unpredictable. The actual slow-cook temperatures don't always match what's advertised in the manual. Also, Instant Pots only heat from the bottom, whereas slow cookers generate heat from the side as well as the bottom of the pot. This recipe needs an old-fashioned crockpot/slow cooker for best results.
  • Prep Time: 10 minutes
  • Cook Time: 10 hours
  • Category: Side Dishes
  • Method: Slow Cooker

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26 comments on “Crockpot Caramelized Onions (Paleo, AIP, GAPS, Wahls, Whole30)”

  1. This was soooo good! I put leftovers in silicone muffin liners and froze, then threw them in a freezer bag. Now I can easily pop out a ‘muffin’ as needed! 😀 Thanks for the great recipe!

  2. This is amazing! Thank you for sharing! I will definitely be adding caramelized onions to everything now. 🙂

  3. I learned to like onions when I learned to caramelize them, and the crockpot version is the best! I only eat Brussel sprouts only when I roast them in the oven usually with bacon and drizzled at the end with a bit of maple syrup – the real stuff! Thanks for these great recipes.

    1. I also sometimes take some of the caramelized onions, put them in a mug with some beef broth, and have an amazing French Onion soup, although I leave out the cheese and croutons, ’cause I can’t have dairy for a while! Again, thank you.

  4. What a unique idea! For GAPS intro, would it be ok to use tallow instead of the olive oil, or would that negatively affect the outcome? Thank you so much!

  5. Thank you for this amazing recipe! I’m going to make some tonight. I fry or saute onions every day in almost every meal and this will help save me a step!! 😀 Thank you thank you thank you.

    p.s.- Can I cook a only 3 cups at the same time, or would they be done in 8 hours instead of 12?

    1. Hi Rachel. Since the onions freeze well, I recommend making a full-sized batch. It will save you far more time. The onions shrink a lot when cooking, so it you started with 3 cups raw, it would be a pretty small amount once fully caramelized. I’m not sure if it would reduce cooking time.

  6. What are some types of onions that are considered “sharp”?
    I really appreciate you and your blog. Thank you!

    1. Anything but vidalias/sweet onions. Regular yellow, white and red onions are all considered “sharp” with red being sharpest.

  7. I am recovering from surgery; anti-inflammatory is a very good thing for me right now (three weeks out and I still have some swelling and bruising) plus detox (the drugs to knock me out for the required 4 hours is still in my system making me sluggish and knackered).
    I’ll be making this soon. Thank yu

  8. Hi Eileen,

    I love this! Thank you so much for sharing. I love caramelized onions but often avoid making them because of the vigilance required to do so. I can’t wait to try this. Thanks again!


  9. These look like something my parents would enjoy. Though they are packed with nutrients, I really can’t bring myself to like onions. :/

    1. Don’t feel bad ~ I can’t bring myself to like brussel sprouts (and believe me, I have tried!) We all have different tastes. 🙂

  10. I just got a large batch of onions in my veggie share this week so I decided to give this a try.
    I was a bit skeptical. Caramelizing onions has always seemed so hard and sort of mysterious — but wow — this totally worked! What a better way to do this! Thanks so much for the great tip.

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