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A close-up of a steaming bowl of classic French Onion Soup, showcasing its melted Gruyère cheese topping.

Perfect French Onion Soup

This French Onion Soup recipe delivers a deeply flavored broth with sweet, caramelized onions and a bubbly, cheese-laden crouton. It's the perfect comforting and authentic experience in a bowl, promising satisfaction every time.
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Prep Time 20 minutes
Cook Time 1 hour 30 minutes
Total Time 1 hour 50 minutes
Servings: 6
Course: Main Course
Cuisine: French
Calories: 450
Ingredients Equipment Method Notes

Ingredients
  

  • 6 large yellow onions, thinly sliced
  • 4 tablespoons butter
  • 2 tablespoons olive oil
  • 1 teaspoon sugar
  • 1/2 teaspoon salt, plus more to taste
  • 1/4 teaspoon black pepper, plus more to taste
  • 8 cups beef broth low sodium preferred
  • 1 cup dry red wine optional
  • 2 tablespoons all-purpose flour
  • 2 bay leaves
  • 1 teaspoon dried thyme
  • 1 baguette, sliced into 1-inch thick rounds
  • 4 tablespoons olive oil
  • 8 ounces Gruyere cheese, shredded
  • Sherry vinegar optional

Equipment

  • Large heavy-bottomed pot or Dutch oven
  • Knife
  • Cutting board
  • Measuring spoons
  • Measuring cups
  • Oven-safe bowls or crocks
  • Baking sheet
  • Oven
  • Broiler
  • Ladle

Method
 

  1. In a large, heavy-bottomed pot or Dutch oven, melt the butter and olive oil over medium heat.
  2. Add the sliced onions, sugar, salt, and pepper. Stir to coat.
  3. Reduce the heat to low and cook, stirring occasionally, for 45-60 minutes, or until the onions are a deep golden brown color.
  4. If the onions start to stick or burn, add a tablespoon or two of water to the pot and scrape up any browned bits from the bottom.
  5. Once the onions are deeply caramelized, sprinkle the flour over them and stir to combine. Cook for 1-2 minutes to cook out the raw flour taste.
  6. Slowly pour in the red wine (if using), scraping up any browned bits from the bottom of the pot. Let the wine reduce slightly for a few minutes.
  7. Pour in the beef broth, add the bay leaves and thyme. Bring to a simmer.
  8. Reduce the heat to low, cover, and simmer for at least 30 minutes, or up to an hour, to allow the flavors to meld.
  9. Remove the bay leaves and season with salt and pepper to taste.
  10. Preheat oven to 375°F (190°C).
  11. Brush both sides of the baguette slices with olive oil.
  12. Arrange the slices on a baking sheet and bake for 8-10 minutes, or until lightly golden brown.
  13. Ladle the soup into oven-safe bowls or crocks.
  14. Top each bowl with one or two toasted baguette slices.
  15. Pile a generous amount of shredded Gruyere cheese on top of the bread.
  16. Place the bowls on a baking sheet and broil for 2-3 minutes, or until the cheese is melted, bubbly, and golden brown. Keep a close eye on them to prevent burning!
  17. Let cool slightly before serving.

Notes

Don't skimp on the onions for a richer flavor. Use quality beef broth for the best results. Caramelizing the onions properly is essential, so be patient. Deglaze the pot by scraping up browned bits for added flavor. Don't over-broil the cheese. Add a splash of sherry vinegar before serving for a tangy twist. Leftover soup can be stored in the refrigerator for up to 3 days and reheated on the stovetop or in the microwave. Add the crouton and cheese topping just before serving.