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Easy Crockpot French Onion Soup with Rich Caramelized Flavor

Close-up of a steaming bowl of crockpot french onion soup topped with a thick slice of toasted bread and melted, bubbly Gruyère cheese.
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Make rich, savory French Onion Soup with minimal effort using your slow cooker. This recipe focuses on deep onion caramelization for classic flavor, topped with melted Gruyère cheese.

Ingredients

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  • 3 pounds yellow onions, thinly sliced
  • 4 tablespoons unsalted butter, cut into pieces
  • 1 tablespoon olive oil
  • 1 teaspoon granulated sugar
  • 1 teaspoon salt
  • 1/2 teaspoon black pepper
  • 2 cloves garlic, minced
  • 1/2 cup dry white wine or dry sherry
  • 6 cups low-sodium beef broth
  • 1 tablespoon Worcestershire sauce
  • 1 bay leaf
  • 1/2 teaspoon dried thyme
  • 1 baguette, sliced 1 inch thick
  • 8 ounces Gruyère cheese, shredded

Instructions

  1. Place the sliced onions, butter, olive oil, sugar, salt, and pepper into your slow cooker.
  2. Cook on LOW for 8 to 10 hours, or on HIGH for 4 to 5 hours, stirring halfway through. The onions should be deeply caramelized and dark brown.
  3. Add the minced garlic to the slow cooker and cook for 10 minutes more.
  4. Pour in the white wine or sherry, scraping up any browned bits from the bottom of the slow cooker. Cook for 15 minutes on HIGH, allowing the liquid to reduce slightly.
  5. Stir in the beef broth, Worcestershire sauce, bay leaf, and thyme.
  6. Cover and cook on LOW for 1 more hour to let the flavors combine. Remove and discard the bay leaf before serving.
  7. Preheat your oven broiler. Arrange the baguette slices on a baking sheet. Toast under the broiler for 1 to 2 minutes per side until lightly golden. Watch closely to prevent burning.
  8. Ladle the soup into oven-safe bowls. Place one or two toasted baguette slices on top of the soup in each bowl.
  9. Generously cover the bread with shredded Gruyère cheese.
  10. Place the bowls on a baking sheet and broil for 2 to 4 minutes, until the cheese is melted, bubbly, and lightly browned. Serve immediately.

Notes

  • For the deepest flavor, cook the onions on the LOW setting for the full 10 hours. This hands-off method develops the best savory onion broth.
  • If you do not have oven-safe bowls, you can melt the cheese on the bread separately on a baking sheet and then float the cheesy croutons on top of the soup just before serving.
  • You can prepare this soup entirely ahead of time. Cool it completely, remove the bay leaf, and store it in the refrigerator for up to 3 days. Reheat gently before the final broiling step.

Nutrition

Find it online: https://kingscook.com/crockpot-french-onion-soup-recipe/