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slow cooker french onion soup

slow cooker french onion soup

This comforting French onion soup, made effortlessly in a slow cooker, captures the rich flavors of caramelized onions and aromatic broth, topped with melted cheese. Perfect for a cozy dinner or as an appetizer.
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Prep Time 15 minutes
Cook Time 6 hours
Total Time 6 hours 15 minutes
Course Appetizer
Cuisine French Cuisine
Servings 4 People
Calories 320 kcal

Equipment

  • 1 slow cooker
  • 1 large frying pan optional for caramelizing onions
  • 1 wooden spoon or spatula
  • 1 ladle
  • 4 soup bowls

Ingredients
  

  • 4 large yellow onions About 2 pounds, thinly sliced.
  • 4 tablespoons unsalted butter
  • 1 teaspoon sugar
  • 8 cups beef broth
  • 1 cup dry white wine Optional.
  • 2 teaspoons fresh thyme Or 1 teaspoon dried thyme.
  • 2 bay leaves
  • Salt to taste
  • Black pepper to taste
  • 8 slices French baguette
  • 1 ½ cups grated Gruyère cheese

Instructions
 

  • If desired, caramelize the onions: In a large frying pan, melt the butter over medium heat. Add the sliced onions, sugar, a pinch of salt, and cook, stirring frequently until golden brown and caramelized (about 25-30 minutes). This step enhances the flavor, but can be skipped to simplify the process.
  • Transfer the caramelized onions (or raw onions if skipped) to the slow cooker. Pour in the beef broth and white wine (if using). Add thyme, bay leaves, salt, and black pepper. Stir well to combine.
  • Cover and cook on low for 6 hours, or until the onions are tender and flavors are well developed.
  • During the last 30 minutes of cooking, preheat your oven to 350°F (175°C).
  • Place the slices of French baguette on a baking sheet. Toast them in the oven for about 10 minutes, or until golden brown.
  • Remove bay leaves from the soup. Taste and adjust seasoning with additional salt and pepper if needed.
  • To serve, ladle the soup into bowls, place a slice of toasted baguette on top, and sprinkle generously with Gruyère cheese.
  • Place bowls under the broiler for 2-3 minutes, until the cheese melts and bubbles. Be careful not to burn the cheese.
  • Serve hot and enjoy!

Notes

If you prefer a vegetarian version, use vegetable broth instead of beef broth.
You can substitute Gruyère cheese with Swiss cheese or mozzarella if desired.
This soup stores well in the fridge for up to 3 days and can be frozen for up to 3 months. Reheat before serving.