Authentic French Onion Soup: A Classic Bistro-Style Recipe with Melted Gruyère

Transform simple ingredients into a rich, deeply flavored soup that captures the essence of French cuisine.

This classic French onion soup features caramelized onions in a rich beef broth, topped with crusty bread and melted cheese.

Difficulty	Medium
Prep Time	15 minutes
Cooking Time	75 minutes
Total Time	90 minutes
Servings	6 people

Ingredients

• 6 large yellow onions, thinly sliced
• 4 tablespoons butter
• 2 tablespoons olive oil
• 1 teaspoon sugar
• 2 cloves garlic, minced
• 8 cups beef stock
• 1/2 cup dry white wine
• 2 bay leaves
• 4 sprigs fresh thyme
• 1 tablespoon flour
• Salt and black pepper to taste

For the Topping:

• 6 slices crusty French baguette
• 2 cups grated Gruyère cheese
• 1/2 cup grated Parmesan cheese
• Fresh thyme for garnish

Instructions

1. Caramelize the Onions
   • Slice onions thinly and uniformly
   • Heat butter and oil in a large pot over medium heat
   • Add onions and sugar
   • Cook for 45-50 minutes, stirring occasionally until deep golden brown
2. Build the Soup Base
   • Add minced garlic and cook for 1 minute
   • Sprinkle flour over onions and cook for 1-2 minutes
   • Add white wine and scrape bottom of pot
   • Pour in beef stock
   • Add bay leaves and thyme sprigs
   • Simmer for 30 minutes
3. Prepare the Topping
   • Slice baguette into 1-inch thick pieces
   • Toast bread slices until golden
   • Preheat broiler
4. Finish and Serve
   • Ladle soup into oven-safe bowls
   • Place toasted bread on top
   • Cover generously with both cheeses
   • Broil until cheese is bubbly and golden brown
   • Garnish with fresh thyme

Additional Tips

• Use yellow onions for the best flavor
• Don’t rush the caramelization process – it’s key to the soup’s flavor
• Choose a good quality beef stock
• Traditional Gruyère can be replaced with Swiss cheese
• Use oven-safe bowls for the final broiling step
• Let the soup rest for a few minutes before serving – it will be very hot