Slow Cooker Caramelized Onions

5 from 1 vote

These Slow Cooker Caramelized Onions are a delicious way to add savory flavor to food, without the hands-on time of the stove-top method.

Prep Time15

Cook Time6

Total Time6 15

Course: Condiment

Cuisine: American

Keyword: caramelized, Caramelized Onions, crock pot, gluten free, onion, onions, slow cooker, vegetarian

Special Diet: Dairy Free, Gluten Free, Nut Free, Vegan, Vegetarian

Servings:

Calories: 100kcal

2 Tablespoons unsalted butter (use Dairy Free butter alternative or replace with 2 Tablespoons extra olive oil if you need this recipe to be Dairy Free or Vegan)
2 Tablespoons olive oil
4 pounds yellow onions
1 Tablespoon brown sugar
2 teaspoons kosher salt
1 teaspoon ground black pepper
1/4 teaspoon dried thyme (optional)

Turn slow cooker on to high. Add 2 Tablespoons unsalted butter and 2 Tablespoons olive oil and cook until butter is melted while you're cutting the onions.
Trim off the non-root-end off of the onions, then remove all the papery peel. Cut the onion in half through the root end. Trim off the root end from both halves, place the onion flat side down, and slice 1/4" thick (with the grain).
Transfer the sliced onions to the slow cooker, and stir in 1 Tablespoon brown sugar, 2 teaspoons kosher salt, 1 teaspoon ground black pepper, and 1/4 teaspoon dried thyme (if using). Cook for 2 hours on high, then reduce to low and cook for an additional 4-6 hours, until onions are very soft and golden brown. Make sure to check your onions often, stirring occasionally. If at any point the onions are burning on the bottom, add a small amount (1-2 Tablespoons) of water. Use caramelized onions immediately, or refrigerate for up to 2 days, or freeze in individual serving sizes for later use.