Slow Cooker Caramelized Onions

Slow Cooker Caramelized Onions let you make a big batch without having to spend an hour at the stove. Just add your sliced onions to the crockpot with some butter and let your crockpot do the work.

It takes 10-12 hours in the slow cooker on Low to make the caramelized onions. This long cook time makes it a great recipe to make overnight! You'll wake up to a big batch of caramelized onions ready to use.

Ingredients for Caramelized Onions:

• Sweet, Yellow Onions - you can use other onions (such as white or regular yellow or even red), but I love the extra sweetness from the sweet onions
• Butter - the butter will be melted and poured over the sliced onions. You can swap in olive oil, if you prefer.
• Salt

How to Make Caramelized Onions in the Crockpot

1. Thinly Slice Onions: Peel the onions and cut in half. Thinly slice the onions into thin half moons. I highly recommend using a mandoline but you can also use a very sharp knife. The thinner you slice the onions, the quicker they'll cook
2. Add to Slow Cooker: Add the thinly sliced onions, melted butter, salt and pepper to the crockpot. It's okay if it's full to the rim as the onions will greatly reduce as they cook.
3. Cook: Cook on low for 10-12 hours, depending on your preference. I like to give them a stir every 2-3 hours for even cooking, but if you're making them overnight then you can skip the stirring step. At 10 hours, they will be lightly browned but have a slight bite. Or you can cook longer for 12+ to get deeper brown onions that are much softer and jammier. If you're going for jammy onions then I recommend leaving the lid slightly ajar for the last couple hours so that some of the liquid can evaporate.

How do you make caramelized onions?

Traditionally, caramelized onions are made on the stove. The process takes about an hour and requires frequent stirring. I love making them on the stove, but sometimes you want a hands off option - especially if you're trying to make a big batch.

What size of slow cooker should be used?

This recipe is written using a large 6-8qt sized slow cooker. But the great thing about this recipe is that you can use more or less onions to fill your slow cooker.

What kind of onions do you use for caramelized onions?

You can use any onion you're like for caramelized onions - yellow, red, white, or sweet yellow. I prefer using sweet yellow onions for the added sweetness. If you use another variety of onion, you can add a spoonful of sugar if you'd like.

Storage and Freezing

Storage: Leftover caramelized onions can be stored in airtight containers in the fridge for up to 5 days.

Freezing: You can even freeze caramelized onions! They're great to add to stews and sauces for a total flavor boost. Store in airtight bags in the freezer for up to 6 months. I like to freeze them in cubes - such as an ice cube tray - for easy portioning.

Recipe Notes and Tips:

• Longer Cook Time = Jammier Onions. The caramelized onions are done as soon as 10 hours and they will be browned, soft, but with a very slight bite. If you continue to cook the onions for 12+hours then they will get darker and a jammy texture.
• Leave Lid Ajar or Drain Liquid - The onions will release moisture as they cook in the covered slow cooker. You can leave the lid ajar for the last few hours of cooking, or at the end you can use a slotted spoon to remove the onions and drain the excess liquid.

Ways to use Caramelized Onions:

• Caramelized Onion and Pancetta Quiche - Skip the onion step in the recipe and just use about ¾ cup of caramelized onions for the filling.
• Caramelized Onion Dip - Mix the onions sour cream, mayo, spices, and chives to make a yummy, creamy dip for chips.
• BBQ Chicken Sliders - Instead of the sliced, raw red onions use caramelized onions on top of the bbq chicken.
• French Onion Baked Potatoes - They're a fun variation on twice baked potatoes and French Onion soup - scoop out the flesh of baked potatoes and mix with caramelized onions, load back in the potato skins, and top with extra onions and shredded cheese.
• One Pot French Onion Pasta - A variation of this recipe went viral on TikTok and has been popular ever since!
• Cheesy Chipotle Turkey Sliders - from the Creative Bite - Turn leftover turkey into delicious sliders filled with caramelized onions, smoky seasoning, and cheddar cheese.
• Use as a Topping! Burgers, pizza, sandwiches, and more.

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