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Slow-Cooker French Onion Soup

Slow-Cooker French Onion Soup

In this genius slow-cooker soup recipe, two types of onions are caramelized for hours before adding a sherry-spiked broth. For a bistro-worthy presentation, ladle the soup into ovenproof crocks, top with the bread and cheese and broil.


8 servings

Prep Time

30 minutes

Total Time

8 1/2 hours



  • 2tablespoons butter, cut into 8 pieces
  • 2tablespoons extra-virgin olive oil
  • 8sprigs fresh thyme
  • 4cloves garlic, smashed
  • 1bay leaf
  • 2pounds yellow onions, halved and sliced
  • 2pounds red onions, halved and sliced
  • 1teaspoon salt
  • 3/4teaspoon ground pepper
  • 4cups low-sodium beef broth
  • 1/4cup dry sherry

Cheese Toasts

  • 8diagonal slices baguette (1/2-inch-thick), toasted
  • 1cup shredded Gruy√®re or Swiss cheese


  1. To prepare soup: Scatter butter in a 6- to 7-quart slow cooker. Add oil, thyme, garlic and bay leaf, then onions. Sprinkle with salt and pepper. Cover and cook on High for 8 hours.
  2. Bring broth and sherry to a boil in a saucepan. Remove the thyme sprigs and bay leaf from the slow cooker. Pour in the broth and cook on High, uncovered, for 10 minutes.
  3. To prepare cheese toasts: Meanwhile, position rack in upper third of oven; preheat broiler to high. Top each baguette slice with 2 tablespoons cheese. Broil until the cheese is melted, 1 to 2 minutes. Divide the soup among 8 bowls. Top each with a cheese toast.


Refrigerate soup (Steps 1-2) for up to 5 days or freeze for up to 3 months. Make cheese toasts before serving.

6- to 7-quart slow cooker

Nutrition Facts

Per serving (recipe makes 8 servings)

Calories 271kcal
Carbohydrate Total 31g
Total Sugars 9g
Added Sugars 0g
Fiber 5g
Total Fat 12g
Saturated Fat 5g
Mono Saturated Fat 5g
Cholesterol 22mg
Sodium 529mg
Protein 12g
Potassium 428mg
Calcium 194mg
Folate 40mcg
Omega-6 1g
Vitamin E 1mg
Zinc 1mg
Vitamin B3 2mg

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