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French Onion Soup

This classic French Onion Soup highlights the slow caramelization of onions, which unlocks their natural sweetness and depth of flavor. Rich beef broth and a toasted baguette topped with melty Gruyère cheese create a hearty, comforting dish with a glossy, golden-brown finish. The final texture is silky and flavorful, with crispy bread providing a satisfying contrast.
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Prep Time 15 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 30 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 3 pounds yellow onions thinly sliced
  • 4 cups beef broth or mushroom broth for vegetarian
  • 0.5 cup dry white wine optional but recommended
  • 1 tablespoon unsalted butter
  • 2 cloves garlic minced
  • 1 sprig fresh thyme optional
  • 1 loaf baguette sliced into rounds
  • 1.5 cups Gruyère cheese grated
  • 2 tablespoons olive oil
  • to taste Salt and pepper

Equipment

  • Large heavy-bottomed pot or Dutch oven
  • Sharp knife and cutting board
  • Baking sheet
  • Oven broiler
  • Ladle

Method
 

  1. Thinly slice the onions evenly, about ¼ inch thick, to ensure uniform caramelization.
  2. Heat your large heavy-bottomed pot over medium-low heat, then add butter and olive oil, allowing them to melt and combine.
  3. Add the sliced onions to the pot, stirring to coat them in the melted butter and oil. Cook slowly, stirring every 10 minutes, until the onions turn a deep, glossy brown—about 45 to 60 minutes. You'll notice a sweet aroma filling your kitchen as they caramelize.
  4. Once the onions are richly browned and fragrant, add the minced garlic and cook for about 1-2 minutes until fragrant, stirring constantly.
  5. Pour in the white wine, scraping up any browned bits from the bottom of the pot to deglaze. Let it cook down for 3-4 minutes until slightly reduced and aromatic.
  6. Add the beef broth and thyme sprig, season with salt and pepper, then bring to a gentle simmer. Let it cook uncovered for 20 minutes to deepen the flavor.
  7. Preheat your oven to 180°C (350°F). Slice the baguette into rounds about ½ inch thick and toast on a baking sheet until golden and crispy, about 10 minutes.
  8. Remove the thyme sprig from the soup, then taste and adjust seasoning as needed. Ladle the hot soup into ovenproof bowls.
  9. Top each bowl with a toasted baguette slice, then sprinkle generously with grated Gruyère cheese.
  10. Place the bowls on a baking sheet and broil in the oven just until the cheese bubbles and turns golden—about 2-3 minutes. Keep a close eye to prevent burning.
  11. Carefully remove from the oven, let sit for a minute, then serve hot, enjoying the rich aroma and bubbling cheese topping.

Notes

Patience during caramelization is key to developing the dish's deep flavor. Feel free to customize with different cheeses or broths to suit your taste.