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Creamy Slow Cooker French Onion Soup

A comforting blend of caramelized onions, rich broth, and melty cheese, this creamy soup is perfect for a cozy night in or entertaining guests.
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Prep Time 10 minutes
Cook Time 7 hours
Total Time 7 hours 10 minutes
Servings: 6 servings
Course: Appetizer, Soup
Cuisine: French
Calories: 450
Ingredients Method Notes

Ingredients
  

Main Ingredients
  • 4 large yellow onions, thinly sliced Opt for sweet onions like Vidalia for better caramelization.
  • 1/4 cup unsalted butter For caramelizing onions.
  • 6 cups beef broth Can substitute with vegetable broth for a vegetarian option.
  • 1 teaspoon sugar To aid in caramelizing the onions.
  • 1 teaspoon thyme Use either dried or fresh thyme.
  • 1/4 cup all-purpose flour For thickening the soup.
  • 1 cup heavy cream Added for creaminess right before serving.
  • to taste Salt and pepper For seasoning.
  • 1 cup shredded Gruyère cheese Or Swiss cheese for topping.
  • Baguette, sliced For serving.

Method
 

Preparation
  1. In a skillet over medium heat, melt the butter.
  2. Add the sliced onions and sugar. Stir occasionally, cooking for about 20-25 minutes until they become soft and caramelized.
Cooking
  1. In your slow cooker, combine the caramelized onions, beef broth, thyme, and salt and pepper. Stir in the flour until just combined.
  2. Cover and cook on LOW for 6-8 hours, or on HIGH for 3-4 hours.
  3. About 30 minutes before serving, stir in the heavy cream and adjust seasoning if needed.
Serving
  1. Ladle the soup into bowls, top with baguette slices, and sprinkle generously with shredded cheese.
  2. Broil in the oven on low until the cheese is bubbly and golden brown.

Notes

For the best flavor, don't rush the caramelization process. Consider using Gruyère cheese for its unique flavor, or any meltable cheese of your preference. Store leftovers in an airtight container in the fridge for up to 3-4 days.