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French Onion Soup

This classic French Onion Soup is built on slow caramelized onions, simmered in rich beef broth, and topped with toasted baguette slices covered in melted Gruyère cheese. The process involves patient slow-cooking to develop deep sweetness and umami, resulting in a comforting, layered broth with a golden, bubbly cheese topping. The final dish boasts a glossy, deep amber hue with crispy bread and gooey cheese, perfect for cozy evenings.
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Prep Time 20 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 35 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 370
Ingredients Equipment Method Notes

Ingredients
  

  • 4-5 large yellow onions preferably sweet varieties
  • 2 tablespoons unsalted butter
  • ½ cup dry sherry or white wine for deglazing
  • 4 cups beef broth or mushroom/vegetable broth for vegetarian
  • Salt and freshly ground pepper to taste
  • 1 French baguette slice cut into ½-inch slices
  • 1 ½ cups Gruyère cheese grated

Equipment

  • Large heavy-bottomed pot or Dutch oven
  • Sharp knife
  • Wooden Spoon
  • Baking sheet
  • Oven-safe bowls

Method
 

  1. Peel and thinly slice the yellow onions, aiming for uniform slices to ensure even caramelization. Set aside.
  2. Melt the butter in a large heavy-bottomed pot over medium-low heat until it begins to foam and smell buttery, about 2 minutes.
  3. Add the sliced onions to the pot, stirring well to coat them with butter. Reduce heat to low and cook, stirring occasionally, until they soften and begin to turn golden, about 15 minutes.
  4. Continue cooking the onions slowly, stirring every 10 minutes. Over the next 45-60 minutes, they will deepen in color, becoming glossy, deep amber and fragrant with a sweet, smoky aroma.
  5. Once the onions are richly caramelized, pour in the dry sherry or white wine, scraping the bottom of the pot with a wooden spoon to deglaze, releasing all those flavorful browned bits. Let cook for 2-3 minutes until the alcohol evaporates and the mixture thickens slightly.
  6. Add the beef broth to the pot, stirring to combine. Season with salt and pepper. Bring the mixture to a gentle simmer and cook uncovered for about 15 minutes to allow flavors to meld and broth to deepen.
  7. While the soup simmers, preheat your oven to 200°C (390°F). Arrange the baguette slices on a baking sheet and toast in the oven for about 5 minutes until golden and crispy.
  8. Remove the toasted bread from the oven and generously sprinkle the grated Gruyère cheese on top. Return to the oven and broil for 5-7 minutes until the cheese is melted, bubbly, and golden brown.
  9. Taste the soup and adjust the seasoning with more salt and pepper if needed. Ladle the hot soup into oven-safe bowls, placing a cheesy toast slice on top of each.
  10. Place the bowls on a baking sheet and broil for an additional 2-3 minutes until the cheese is golden and bubbly. Carefully remove from the oven and serve immediately, enjoying the rich aroma and layered textures.

Notes

Slow caramelization is key to deep flavor. Use a heavy pot to prevent burning, and patience is essential. You can prepare the caramelized onions a day ahead and reheat before assembling the soup.