Ingredients:

  • 3 lbs yellow onions, thinly sliced
  • 2 tbsp unsalted butter
  • 1 tbsp neutral oil
  • 1/2 tsp kosher salt
  • 1/4 tsp black pepper
  • 1 tbsp brown sugar
  • 1 tsp balsamic vinegar

Instructions:

  1. Slice the onions into uniform, thin half-moons and place them into the slow cooker.
  2. Add the butter, neutral oil, salt, and pepper. If using brown sugar, stir it in now. Toss the onions gently with the fats until evenly coated.
  3. Cover the slow cooker with a lid and set to LOW for 8 hours.
  4. Remove the lid and stir the mahogany brown onions thoroughly to incorporate juices. Stir in balsamic vinegar if desired for a glossy finish.