Slow Cooker Caramelised Onions

Slow Cooker Caramelized Onions make it easy to turn onions into something rich and flavorful. Just add everything to the crock pot and let time do the work! Perfect for soups, burgers, dips, and more.

Caramelized onions are one of those ingredients that can transform simple meals into something satisfying.

When onions cook slowly, their natural sugars deepen and develop, giving you a rich sweetness and a soft, jam-like texture.

I used to stand at the stove stirring a skillet of onions for nearly an hour to get that flavor, and while the result was worth it, I always felt tied to the pan.

Once I started making slow cooker caramelized onions in my crockpot, I realized how much time and attention I could save.

This approach does not require constant monitoring. I can set it up in the morning (or before bed) and come back to perfectly tender, golden onions.

These onions fit into so many dishes.

I add them to sandwiches for depth. I stir them into pasta to add sweetness.

I use them on pizza (pile some onto Vegetarian Sausage Skillet Pizza), in soups (awesome in Miso Sweet Potato Soup), and even in savory dips.

It is also a great way to use a large bag of onions before they start to sprout!

Jump to:

• Why You'll Love This Recipe
• Onions
• What are Caramelised Onions?
• Ingredients
• Instructions
• Serving Suggestions
• Variations
• Storage
• Recipe Tips
• FAQs
• 📖 Recipe
• 💬 Comments

Why You'll Love This Recipe

• Slow cooker caramelization avoids the need to stand over a stove.
• The recipe scales easily for batch cooking and meal prep.
• The sweet and savory flavor pairs well with many everyday dishes.
• Leftovers keep well in the fridge or freezer.
• Simple ingredients make this an accessible recipe for beginners.

Onions

Onions contain natural sugars that develop more flavor when cooked slowly at low heat. When rushed, onions brown unevenly or burn.

A slow cooker maintains an even temperature, allowing the onions to soften and caramelize properly.

The bit of butter helps with richness, while the sugar encourages even browning without overpowering the flavor.

What are Caramelised Onions?

Caramelised onions are onions that have been cooked slowly until they turn soft, sweet, and deep golden brown.

As they cook, their natural sugars break down and create a rich, mellow flavor.

They can be used to add depth to many dishes like burgers, soups, pizzas, and sandwiches.

Caramelized onions appear in many cuisines. They show up in French onion soup, Italian pasta sauces, Indian biryanis, and Middle Eastern stews.

The slow cooker method is simply a modern convenience approach to a very old cooking technique involving time and gentle heat.

Ingredients

• Onions. Any variety can work, but yellow onions offer a balanced flavor. Red onions become deeper and sweeter, while white onions remain milder.
• Butter. Adds richness and helps the onions brown evenly. Substitute with olive oil or vegan butter if preferred.
• Sugar. Helps support browning and enhances the natural sweetness of the onions. You can use honey or omit entirely if you prefer less sweetness.

See the recipe card for quantities.

Instructions

Follow this step-by-step photo tutorial, then scroll down to the recipe card for the full ingredients list and method.

Peel and slice the onions finely.

You can do it with a knife, mandolin or food processor.

Add the onions to the slow cooker (it will be quite full, but will reduce as it cooks).

Add the butter and sugar and gently stir to combine slightly.

Cook on low, with the lid on, for 8-10 hours.

Four hours of slow cooking.

Six hours of slow cooking.

Eight hours of slow cooking.

Ten hours of slow cooking (with the lid off for the final 30 minutes).

If it's not cooking overnight, you can give it a stir every few hours, but this isn't essential.

Your onions should be brown and caramelised. If it still has a lot of moisture, you can remove the lid and cook it for a further half hour or so until it evaporates.

Serving Suggestions

• Spread onto toasted bread. Try it on Turmeric Bread or Wheaten Bread.
• Stir into mashed potatoes and top with Mushroom Gravy.
• Use as a burger or sandwich topping. Try these 25 Vegan Sandwiches.
• Add to pizza before baking.
• Stir into pasta sauces.
• Serve with roasted vegetables.
• Add to omelets or scrambled eggs.
• Mix into dips like hummus or sour cream dip. Try it in French Onion Dip.
• Add to soups for extra flavor.
• Stir into risotto. Try it in this Slow Cooker Mushroom Risotto.
• Add to grilled cheese sandwiches.
• Use on flatbread with goat cheese.

Variations

• Use olive oil or vegan butter instead of butter for a dairy-free version.
• Add a splash of balsamic vinegar near the end for a tangy finish.
• Add garlic slices during the last two hours of cooking for a more savory profile.
• Cook with thyme or rosemary added near the end to add an herbal note.

Storage

Store caramelized onions in an airtight container in the refrigerator for up to one week.

To freeze, place them in small freezer-safe containers or silicone cubes, freeze, then transfer to a freezer bag.

They can be reheated in a skillet or microwave. This makes them useful for quick meals when time is limited.

FAQs

⭐⭐⭐⭐⭐ If you love this recipe, please leave a five-star rating and review in the comments below! And if you make any modifications, let us know how it went so that we can all benefit from your experience. Happy cooking!

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