Let the slow cooker do the work for this flavourful French style Caramelized Onion soup.
- Yellow Onions - 3 pounds peeled, sliced, and cut into quarter-moons
- unsalted butter, melted - 2 tbsp
- kosher salt - 1 tsp
- Caramelized Onion Garlic Seasoning - 1 tbsp
- Black pepper - freshly ground
- Beef Broth - 10 cups
- Balsamic Vinegar with Garlic - 2 tbsp
- Brandy or Sherry ( optional ) - 3 tbsp
- To serve -
- Toasted Baguette slices - 4 to 6 per bowl
- Gruyere Cheese - 1/3 cup grated
- Equipment: -
- 5 quart or larger slow cooker -
- Oven safe soup bowls -
- Rimmed baking sheet -
- Cutting board and knife -
- Season the onion. Place the onions in slow cooker, stir in the butter, oil, salt and generous amount of pepper.
- Cover and cook on the LOW setting overnight until onions should be dark brown golden-brown and soft, 12 hours or overnight.
- Stir in the hot broth and Garlic Balsamic Vinegar.
- Cover and continue cooking on LOW setting for 6-8 hours. This is flexible; as long as you slow cooker holds moisture well ( wrap a towel over the lid if quite a lot of steam escapes), you can cook the soup for hours. Longer cooking will only intensify the flavours. Taste and season with more salt and pepper if needed, and stir in the brandy or sherry if using.
- Arrange a rack in the upper third of the oven and heat to 350 F. Ladle the soup and onions into oven safe bowls and place the bowls on a rimmed baking sheet.
- Top each bowl with a slice of toast and a generous quantity of shredded Gruyere cheese, about 1/3 per bowl.
- Bake until the cheese is completely melted, 20-30 min.
- Turn the oven to broil. Broil until the cheese is bubbling and browned, 2-3 minutes. Remove from the oven and let cool for a few minutes.
Note: If soups seems a little thin or watery, you can quickly finish it off on the stovetop by simmering gently in a saucepan for 15 minutes or until the broth has reduced a little.