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–+ servings
slow cooker onion soup

French Onion Soup Slow Cooker

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Prep Time 20 minutes
Cook Time 8 hours
Resting Time 5 minutes
Total Time 8 hours 25 minutes
Course Soup
Cuisine French
Servings 6 servings

Equipment

  • 1 slow cooker
  • 1 large skillet
  • 1 Wooden spoon
  • 1 Cutting board
  • 1 sharp knife
  • 1 Ladle
  • 6 oven-safe soup bowls

Ingredients
  

  • 6 large onions thinly sliced
  • 3 tablespoon unsalted butter
  • 1 tablespoon olive oil
  • 1 tablespoon sugar
  • 2 clove garlic minced
  • 1/4 cup all-purpose flour
  • 1/2 cup dry white wine
  • 8 cup beef broth
  • 1 bay leaf
  • 1 teaspoon dried thyme
  • Salt and pepper to taste
  • 1 loaf French baguette sliced
  • 2 cup Gruyère cheese grated

Instructions
 

  • Melt butter with olive oil in a large skillet over medium heat.
  • Add onions and sugar, then sauté until caramelized, about 25 minutes.
  • Stir in garlic and flour, cooking for another minute.
  • Deglaze the skillet with white wine, stirring well.
  • Transfer the onion mixture to the slow cooker.
  • Add beef broth, bay leaf, and thyme to the slow cooker.
  • Season with salt and pepper.
  • Cover and cook on low for 8 hours.
  • Preheat the oven broiler.
  • Ladle soup into oven-safe bowls, top with baguette slices, and sprinkle with Gruyère cheese.
  • Place bowls on a baking sheet and broil until cheese is bubbly and golden, about 2-3 minutes.
  • Remove from oven and let rest for 5 minutes before serving.

Notes

For the best flavor, ensure the onions are deeply caramelized before adding them to the slow cooker. This step enhances the sweetness and depth of the soup. Additionally, using oven-safe bowls allows you to achieve that perfect, gooey cheese topping right before serving.
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