French Onion Soup

This classic French Onion Soup features deeply caramelized onions simmered in a rich beef broth, topped with crusty bread and melted Gruyère cheese. It’s a deeply flavorful and satisfying appetizer or light meal.

French Onion Soup
  • Prep time: 17 minutes
  • Cook time: 40 minutes
  • Total time: 57 minutes
  • Servings: 6
  • Difficulty: Easy
  • Cuisine: International

Ingredients

  • 4 tablespoons unsalted butter
  • 2 tablespoons olive oil
  • 4 large yellow onions (about 3 lbs), thinly sliced
  • 1 teaspoon granulated sugar
  • 1/2 teaspoon salt, plus more to taste
  • 1/4 teaspoon black pepper, plus more to taste
  • 1/4 cup dry sherry or brandy (optional)
  • 8 cups beef broth
  • 2 sprigs fresh thyme, or 1/2 teaspoon dried thyme
  • 1 bay leaf
  • 4 thick slices of baguette or country bread
  • 1 1/2 cups shredded Gruyère cheese

Instructions

  1. In a large, heavy-bottomed pot or Dutch oven, melt butter with olive oil over medium-low heat.
  2. Add the thinly sliced onions, sugar, salt, and pepper. Cook, stirring occasionally, for 45-60 minutes, or until the onions are deeply caramelized, soft, and golden brown. Be patient; low and slow is key.
  3. If using, add the sherry or brandy and scrape up any browned bits from the bottom of the pot. Cook for 2-3 minutes until mostly evaporated.
  4. Pour in the beef broth, add the thyme sprigs and bay leaf. Bring to a simmer, then reduce heat, cover, and cook for at least 30 minutes to allow flavors to meld.
  5. Remove thyme sprigs and bay leaf. Season the soup with additional salt and pepper to taste.
  6. While the soup simmers, toast the baguette slices until golden brown and crisp.
  7. Ladle the hot soup into oven-safe bowls. Place one or two toasted bread slices on top of the soup in each bowl.
  8. Generously sprinkle shredded Gruyère cheese over the bread. Place bowls on a baking sheet and broil for 2-4 minutes, or until the cheese is melted, bubbly, and lightly browned. Watch carefully to prevent burning.

Tips

  • Caramelizing the onions properly is the most crucial step for flavor; do not rush it.
  • Use good quality beef broth for the best flavor base.
  • Broil the soup in a broiler-safe dish or on a baking sheet to catch any spills.

Frequently Asked Questions

Can I make this soup ahead of time?

Yes, the soup base (without the bread and cheese) can be made up to 2 days in advance and stored in the refrigerator. Reheat the soup thoroughly before proceeding with toasting the bread and broiling.

What kind of cheese can I use?

Gruyère is traditional and melts beautifully with a nutty flavor. Swiss cheese, Emmental, or even a sharp white cheddar can be used as substitutes.

Can I make this soup vegetarian?

You can make a vegetarian version by using a rich vegetable broth and omitting the sherry/brandy if it contains animal products. The flavor will be different but still delicious.