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Classic French Onion Soup

French onion soup is a warm, hearty dish featuring caramelized onions simmered in beef broth, topped with toasted slices of baguette and melted cheese. The soup develops a rich, sweet flavor through slow cooking of onions, resulting in a thick, flavorful broth with a satisfying, cheesy crust on top.
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Prep Time 15 minutes
Cook Time 45 minutes
Total Time 1 hour
Servings: 4
Course: Main Course
Cuisine: French
Calories: 320
Ingredients Equipment Method Notes

Ingredients
  

  • 4 large yellow onions thinly sliced
  • 2 tablespoons unsalted butter
  • 1 teaspoon salt
  • 1/2 teaspoon fresh thyme optional
  • 1 cup dry white wine or extra beef broth
  • 6 cups beef broth or vegetable broth for a vegetarian version
  • 8 slices French baguette sliced and toasted
  • 1 1/2 cups grated Gruyère cheese
  • black pepper to taste

Equipment

  • Large Soup Pot
  • Saute pan
  • Baking sheet
  • Oven-safe Bowls or Ramekins

Method
 

  1. Slice the onions thinly and prepare all ingredients for quick assembly.
  2. Melt the butter in a large soup pot over medium heat. Add the sliced onions and sprinkle with salt. Cook, stirring occasionally, until the onions become soft and begin to turn golden, about 10-15 minutes.
  3. Reduce the heat to low and continue to cook the onions, stirring frequently, until they are deeply caramelized and rich in color, about 30 minutes. The onions will smell sweet and look dark golden brown.
  4. Pour in the white wine or extra broth to deglaze the pan, scraping up any browned bits from the bottom. Let simmer until the liquid reduces slightly, about 5 minutes.
  5. Add the beef broth and thyme to the pot. Bring the mixture to a gentle simmer and cook uncovered for 15-20 minutes, allowing the flavors to meld and the soup to thicken slightly.
  6. While the soup simmers, toast the baguette slices until golden and crispy.
  7. Preheat your oven's broiler. Ladle the hot soup into oven-safe bowls or ramekins.
  8. Place a toasted baguette slice on top of each bowl of soup, then generously sprinkle grated Gruyère cheese over the bread and around the edges.
  9. Transfer the bowls under the broiler and cook until the cheese is bubbling and golden brown, about 2-3 minutes. Keep a close eye to prevent burning.
  10. Remove the bowls from the oven carefully, season with freshly ground black pepper, and serve hot, enjoying the crispy, cheesy top with the flavorful broth beneath.

Notes

Caramelizing the onions slowly is key to developing their sweetness and depth of flavor. Feel free to add a splash of sherry for extra richness or top with fresh herbs for garnish.