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Crockpot French onion soup in a spoon.

Crockpot French Onion Soup

Katerina | Diethood
This crockpot French onion soup is an easy take on a French favorite with the same buttery goodness. Add bread and cheese for a fancy meal!
Servings : 6 servings
Prep Time 10 minutes
Cook Time 11 hours 40 minutes
Total Time 12 hours


  • 6 sweet onions,
  • 4 tablespoons unsalted butter, melted
  • ¼ teaspoon sugar
  • ½ teaspoon salt
  • ½ teaspoon fresh ground black pepper
  • 4 to 6 sprigs fresh thyme
  • 1 bay leaf
  • 6 cups low sodium beef broth
  • ½ cup dry white wine
  • salt and fresh ground black pepper, to taste
  • 6 slices french bread optional
  • cups shredded gruyere cheese, optional


  • Place sliced onions in a 6 quart slow cooker.
  • Stir in the melted butter, sugar, salt, and pepper. Top with thyme and bay leaf, COVER, and cook on LOW for about 8 hours or until onions are browned and caramelized. Stir halfway through. 
  • Once onions are caramelized, stir in the beef broth and wine. Taste for salt and pepper and season accordingly.
  • Cover and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through.
  • Remove the lid and discard the thyme and bay leaf. Ladle the soup into ovenproof bowls and transfer the bowls to a large baking sheet.
  • Top the soup in the bowls with a slice of French bread and shredded cheese.
  • Turn the oven-broiler to High.
  • Broil the soups in the oven until the cheese is melted, about 2 to 3 minutes.
  • Remove from oven and serve.


  • For a lighter option, omit the bread and cheese.
  • For a quicker version, start the soup on the stovetop. Mix onions, butter, sugar, salt, and pepper in a big skillet. Cook until they're brown and caramelized, around 25 minutes. Then, shift the onions into the slow cooker, and add beef broth, wine, thyme, salt, and pepper. Let it cook for 6 hours on LOW. When done, pour it into oven-safe bowls, add a baguette slice to each bowl, sprinkle shredded cheese on top, and broil until the cheese melts.
  • Keep a close watch on those onions. It's a narrow line between lovely golden caramelized onions and scorched ones. Once they're caramelized, pull the pan off the heat to avoid a bitter soup.
  • Use croutons: If you're out of French bread, swap it for your favorite croutons to get that same crunchy bite.


Calories: 468 kcal | Carbohydrates: 62 g | Protein: 18 g | Fat: 15 g | Saturated Fat: 8 g | Cholesterol: 42 mg | Sodium: 360 mg | Potassium: 971 mg | Fiber: 4 g | Sugar: 18 g | Vitamin A: 425 IU | Vitamin C: 15.9 mg | Calcium: 240 mg | Iron: 3.4 mg

Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.

Course: Soup
Cuisine: French
Keyword: crockpot french onion soup, french onion soup, french onion soup recipe, how to make french onion soup, slow cooker french onion soup