Slow Cooker Caramelized Onions

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Did you know you can make caramelized onions in a slow cooker? They’re perfectly sweet and jammy, and take so much less effort than making them on the stovetop.

You can make these caramelized onions ahead of time and store them in the fridge, or freeze them for later use. That way you’ll always have some on hand!

A small blue bowl filled with slow cooker caramelized onions on a white marble background.

What you’ll love about this recipe:


  • Rich, Deep Flavor. Slow cooking brings out the natural sweetness of the onions, creating an incredible depth of flavor
  • Meal Prep Friendly. This recipe can be easily prepared in advance, making it perfect for meal planning and saving you time throughout the week. You’ll love discovering new ways to incorporate these delicious onions into favorite dishes, from burgers and sandwiches to steaks and macaroni and cheese.
  • Hands-Off Preparation. Set your slow cooker and let them cook all day. There’s no need to babysit a pan on the stove.

The Best Hands-Off Kitchen Hack For perfect Caramelized Onions

Caramelized onions are one of the most delicious foods around, but making them is a pain in the butt. They seem to take forever and require an attentive eye and constant supervision to make sure they don’t burn.

That is, until now.

Did you know you can make caramelized onions in your slow cooker? This ingenious method takes the traditional process to a whole new level!

With this hands-off approach, you can simply set it and forget it. No more standing over a hot stove, stirring and waiting for the onions to reach that perfect caramelization!

Caramelizing your onions in the slow cooker takes longer than on the stovetop but it’s totally worth it for the intensified aromatic flavor and depth of golden brown color you get.

As someone who loves to cook but also values efficiency, I can confidently say that slow cooker caramelized onions are a complete game changer. Ready to make them? Let’s get cooking!

An overhead view of the ingredients needed to make caramelized onions in a slow cooker: just thinly sliced onions and a pat of butter.

Ingredients

To make caramelized onions in your slow cooker, you only need 2 ingredients:

  • Yellow Onions. You’ll want to stick with using yellow onions for this recipe since they are the best for caramelizing and have a nice sweetness that other types of onions don’t. If you like sweeter onions, you can throw a Vidalia or two into the mix, but using all sweet onions can be pretty overpowering.
  • Butter. A pat of butter gives these onions their delicious flavor. You can use either salted or unsalted butter for this recipe, so go ahead and grab whatever you have in the fridge!

Slow Cooker Caramelized Onions Tips and Variations

  • Easily double this recipe if you require additional caramelized onions for recipes and meals. 
  • You can use olive oil instead of butter when making your caramelized onions. While there’s no exact ratio for replacing butter, a good rule of thumb is to use ¾ the amount of butter called for in the recipe. Since my recipe calls for 1 Tablespoon of butter, if you opt for olive oil then use around ¾ Tablespoon of oil.
  • While it’s not necessary, you are welcome to add some salt (about ½ teaspoon) to your onions before cooking. 
  • Don’t add any additional liquid! It might seem unusual nto to add any liquid to your crock pot before turning it on, but the onions will release plenty on their own once they start to heat up.

After 10 hours of slow cooking, your onions should reach that beautiful golden brown color and have lost most of their liquid. If you love jammier caramelized onions with a deeper color, then continue cooking on LOW for another 3-5 hours, keeping the lid of your slow cooker slightly ajar to allow the liquids to evaporate.

Pro Tip: Make sure to check on your onions every hour if you’ve opted for a longer cooking time and stop cooking as soon as you’re happy with the consistency and color of your onions. 

How to store caramelized onions

Whether you have leftover caramelized onions or you plan on making your onions ahead of busy times, you’ll be happy to know that they can easily be stored in the refrigerator or the freezer.

In the Refrigerator: Store your caramelized onions in the refrigerator for up to 1 week. To reheat, simply add them to a microwave-safe bowl and reheat for 20-30 seconds or add your onions to a skillet over medium-low heat for just a few minutes, paying careful attention that they don’t burn. 

In the Freezer: Your Slow Cooker Caramelized Onions will freeze well for up to 3 months when stored in an airtight container. When ready to use, thaw overnight in the refrigerator and then reheat as you would have if they were refrigerated.

Whether you opt to store your caramelized onions in the fridge or freezer, make sure they have completely cooled first before transferring them to an airtight container for storage. You’ll also want to keep the remaining liquid from the slow cooker separate from your stored onions – it’s super delicious to use in other recipes as a broth and can also be refrigerated or frozen for later use!

Can I leave my onions unattended?

Absolutely! While your onions are cooking in the slow cooker on the LOW setting for 8-10 hours, you don’t need to supervise the cooking at all.
With that said, if you are around your kitchen you can definitely check on your onions and give them a stir which will help to cook them more evenly but this is totally up to you!

You might not be able to stop peeking since they’ll fill your house with a completely irresistible aroma, but try not to open the lid too many times since it can affect the cooking process.

Recipes To Use These Caramelized Onions:

Use these sweet and jammy caramelized onions as a topping for homemade pizza, tarts, or over various meats. Try stirring them into your favorite macaroni and cheese — it’s out of this world.

Here are a few more options:

You can also add beef broth to transform them into a fantastic onion soup like I did in my Slow Cooker Meal Prep Cookbook! Or add a tablespoon or two of balsamic vinegar as they cook for an easy twist on my onion jam recipe.

Overhead view of a blue bowl filled with slow cooker caramelized onions on a white background.You’ll never believe how easy it is to make perfect caramelized onions in a slow cooker. They're sweet, savory, and oh so delicious! You can make these onions ahead of time and store them in the fridge, or freeze them for later use. That way you'll always have caramelized onions on hand!
Slow Cooker Caramelized Onions 1

Slow Cooker Caramelized Onions

Discover the convenience and deliciousness of slow cooker caramelized onions! This hands-off method delivers rich, deep flavor while saving you time in the kitchen.
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Course: slow cooker recipes
Cuisine: American
Prep Time: 5 minutes
Cook Time: 10 hours
Total Time: 10 hours 5 minutes
Servings: 1 1/2 cups
Calories: 51kcal

Ingredients

  • 5 yellow onions thinly sliced
  • 1 tablespoon butter

Instructions

  • Add the onions and butter to your slow cooker
  • Cover the slow cooker and cook on low heat for 8-10 hours, until the onions are deeply caramelized and fragrant. To help prevent burning, give them an optional stir after about 6 hours.
Nutrition Facts
Slow Cooker Caramelized Onions
Amount Per Serving (1 /4 cup)
Calories 51 Calories from Fat 18
% Daily Value*
Fat 2g3%
Saturated Fat 1g6%
Polyunsaturated Fat 1g
Cholesterol 5mg2%
Sodium 18mg1%
Carbohydrates 8g3%
Fiber 1g4%
Sugar 4g4%
Protein 1g2%
* Percent Daily Values are based on a 2000 calorie diet.
Tried this recipe?Mention @HealthyDelish or tag #HealthyDelish!
lauren

Hi, I'm Lauren!

I'm a certified plant-based cook and enthusiastic omnivore who loves looking for creative ways to make weeknight meals more nutritious. I'm the author of Heathy Eating One Pot Cookbook and Healthy Meal Prep Slow Cooker Cookbook. I also blog at The Busy Foodie. Read more...

 

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