Go Back
Slow Cooker French Onion Soup
Alyssa

Slow Cooker French Onion Soup

Enjoy Slow Cooker French Onion Soup—rich, savory broth with caramelized onions, topped with crusty bread and melted cheese. Perfect comfort food.
Print Recipe Pin Recipe
Ingredients Method

Ingredients
  

  • 6 large yellow onions thinly sliced: The star of the dish, yellow onions add sweetness and depth once caramelized.
  • 4 tbsp unsalted butter: This is essential for sautéing the onions and adds a rich flavor.
  • 2 tbsp olive oil: Incorporating olive oil helps prevent the butter from burning providing a perfect base for the onions.
  • 1 tbsp sugar: Sugar helps in the caramelization process enhancing the natural sweetness of the onions.
  • 1 tbsp all-purpose flour: This will help thicken the soup slightly lending it a wonderful texture.
  • 8 cups beef broth: A key ingredient that brings savory richness to the soup. For a lighter version you can use chicken broth.
  • ½ cup dry white wine: Adds acidity and depth of flavor; feel free to omit it if you prefer an alcohol-free dish.
  • 3 sprigs fresh thyme: Imparts a subtle earthiness that complements the onions beautifully.
  • 2 bay leaves: Infuses the soup with additional flavor during cooking.
  • Salt & pepper to taste: Essential for enhancing and balancing flavors throughout the dish.
  • 1 baguette sliced: A crusty baguette is perfect for topping the soup and soaking up the flavors.
  • 2 cups shredded Gruyère cheese: A rich nutty cheese that creates that iconic gooey topping.

Method
 

  1. Melt the butter and olive oil: In a skillet over medium heat, combine 4 tbsp of unsalted butter and 2 tbsp of olive oil until melted and foamy.
  2. Cook the onions: Add 6 thinly sliced large yellow onions. Sauté for about 10-15 minutes until the onions are soft and translucent.
  3. Caramelize the onions: Stir in 1 tbsp of sugar and continue to sauté for an additional 10-15 minutes, cooking until the onions turn a deep, golden brown.
  4. Add flour: Sprinkle 1 tbsp of all-purpose flour over the onions and cook for 2 more minutes to remove the raw flour taste.
  5. Transfer to the slow cooker: Carefully pour the caramelized onions into your slow cooker.
  6. Add broth and seasonings: Pour in 8 cups of beef broth (or chicken broth for a lighter touch), along with ½ cup of dry white wine, 3 sprigs of fresh thyme, 2 bay leaves, and salt and pepper to taste.
  7. Slow cook: Set your slow cooker to low and let it cook for 6-8 hours, allowing all the flavors to meld together beautifully.
  8. Broil the soup: Once the cooking time is complete, preheat your broiler. Ladle the soup into oven-safe bowls.
  9. Top with baguette and cheese: Place a slice of 1 baguette on top of each bowl of soup and generously sprinkle with 2 cups of shredded Gruyère cheese.
  10. Broil to finish: Broil the bowls until the cheese is bubbly and golden, about 2-3 minutes. Watch closely to avoid burning!
  11. Serve hot: Garnish your soup with fresh thyme and serve hot, enjoying the delightful flavors.