Filed Under: 20 Minute Supper Club, Dinner, Food, Lunch, Recipes, soup, Under 20 Mins

Slow Cooker French Onion Soup

Here’s a great way to caramelize onions in the slow cooker. Onions cook up golden brown and sweet with slightest effort. This soup has a few steps but each one requires minimal time and finishing the soup is very easy.

March 18th, 2014

Chef's tip:  Bread can be toasted and stored covered in a dry place up to 2 days ahead of serving soup. If you don’t have a heatproof bowl, mound cheese onto toast after turning and broil until melted and bubbling. Float toast on soup just before serving.
Makes 4 dinner servings, or 6 smaller servings
Prep Time
20 minutes
Cook Time
Total time: 8-10 hours
  • 3 large Spanish onions, peeled, halved and thinly sliced (about 6 cups)
  • 2 tbsp olive oil, plus more for bread
  • 1 tbsp butter
  • 1 tbsp brown sugar
  • 1 tsp kosher salt
  • 4 cups beef stock
  • 2 tbsp dry sherry
  • 1/2 tsp fresh thyme leaves
  • 1/2 baguette, cut into thin slices
  • 1 cup shredded Gruyere cheese
  1. In a slow cooker, toss onions, olive oil, butter, brown sugar and salt, cover entire top of slow cooker with two layers of paper towel and secure with lid. This will catch any excess condensation in slow cooker and allow onions to turn golden brown. Cook on low until onions are soft and caramelized, about 8 hours. This can go longer to about 10 hours, if necessary.

  2. Turn slow cooker to high, add beef stock, sherry and thyme. Cover and cook 30 to 45 minutes. Season to taste with salt and freshly ground black pepper.

  3. Meanwhile, preheat broiler. Arrange bread slices on a sheet pan and lightly brush both sides with olive oil. Set under the broiler and broil, turning once, until lightly toasted on both sides, about 3 minutes.

  4. Ladle soup into oven-safe bowls. Cover each bowl with a piece of toasted bread and cover with cheese. Place bowls under broiler until cheese is golden and bubbling, about 4 to 5 minutes.

Slow Cooker French Onion Soup
Photography by Carlo Mendoza

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