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French Onion Soup
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French Onion Soup

If you’ve ever craved a bowl of deeply flavorful, comforting soup that feels like a warm hug on a chilly day, French Onion Soup is your go-to. This classic French dish is famed for its rich, caramelized onions simmered to perfection in savory beef broth, topped with crusty toasted bread and melted cheese.
Course Soup
Cuisine French
Prep Time 15 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 30 minutes
Servings 4
Calories 350kcal

Ingredients

  • 4 large yellow onions about 3 pounds, thinly sliced
  • 3 tablespoons unsalted butter
  • 1 tablespoon olive oil
  • 1 teaspoon salt
  • 1 teaspoon sugar helps with caramelization
  • 4 cups beef broth or vegetable broth for vegetarian option
  • 1 cup dry white wine or dry sherry optional, adds depth
  • 2 teaspoons fresh thyme leaves or 1 teaspoon dried thyme
  • 1 bay leaf
  • Salt and freshly ground black pepper to taste
  • 1 baguette sliced into 1/2-inch rounds
  • 2 cups shredded Gruyère cheese can substitute with Swiss or mozzarella

Instructions

  • Caramelize the Onions: Heat butter and olive oil in a large pot over medium heat. Add the sliced onions, salt, and sugar. Cook slowly, stirring frequently, for about 45-60 minutes until onions turn deep golden brown and sweetly caramelized. Patience is key here — don’t rush this step as it builds the soup’s rich flavor foundation.
  • Deglaze the Pot: Pour in the white wine or sherry to deglaze, scraping up any brown bits stuck to the bottom of the pot. This adds complexity to the soup’s flavor. Let the alcohol cook off for 2-3 minutes.
  • Add Broth and Herbs: Stir in the beef broth, thyme, and bay leaf. Bring to a gentle simmer and cook uncovered for another 30 minutes. Season with salt and pepper to taste. This simmering melds the flavors perfectly.
  • Prepare the Bread: While the soup simmers, preheat your oven to 400°F (200°C). Arrange the baguette slices on a baking sheet and toast until golden and crisp, about 5-7 minutes per side. Set aside.
  • Assemble the Soup Bowls: Remove the bay leaf from the soup. Ladle the soup into oven-safe bowls or crocks, placing 1-2 toasted bread slices on top of each. Generously sprinkle shredded Gruyère cheese over the bread.
  • Melt the Cheese: Place the bowls on a baking sheet and transfer to the oven. Broil on high for 2-5 minutes, watching closely, until the cheese is bubbly, golden, and slightly browned. Carefully remove and serve immediately while hot and gooey.

Notes

  • Take your time caramelizing onions: The depth of flavor depends on slow, patient cooking. Stir frequently to prevent burning but let the onions brown evenly.
  • Use quality broth: Homemade or high-quality beef broth makes a noticeable difference in richness. For vegetarians, mushroom broth adds umami.
  • Toast bread well: The bread should be sturdy and crisp enough to hold the soup without becoming soggy too fast. Slightly stale baguette works beautifully.
  • Watch the broiler carefully: Cheese can burn quickly. Keep a close eye and remove once bubbly and golden brown.