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French Onion Soup

This classic French Onion Soup relies on slow caramelization of thinly sliced onions to develop deep sweetness and rich flavor. The onions are cooked gently until golden and silky, then simmered in savory broth and topped with toasted bread and melted Gruyère cheese, creating a comforting, layered dish with a golden, bubbly crust and tender onion base.
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Prep Time 15 minutes
Cook Time 1 hour
Total Time 1 hour 15 minutes
Servings: 4
Course: Main Course
Cuisine: French
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • 4 large yellow onions thinly sliced
  • 2 tablespoons unsalted butter for caramelizing
  • 1 tablespoon olive oil to prevent burning
  • 3 cloves garlic minced
  • 4 cups beef broth or vegetable broth for vegetarian
  • 1 teaspoon fresh thyme or dried, added at the end
  • 1 slice French baguette sliced and toasted
  • 1 1/2 cups Gruyère cheese grated

Equipment

  • Large heavy-bottomed pot or Dutch oven
  • Wooden spoon
  • Sharp knife
  • Cutting board
  • Ovenproof bowls
  • Baking sheet
  • Toaster or oven

Method
 

  1. Start by peeling and thinly slicing the onions into about 1/8-inch slices. Set aside.
  2. Heat a large heavy-bottomed pot over medium-low heat, then add the butter and olive oil. Once melted and fragrant, add the sliced onions and a pinch of salt. Cook slowly, stirring every 5–7 minutes, until the onions turn a deep golden amber and smell sweet, about 30-40 minutes.
  3. Add the minced garlic to the caramelized onions and cook for 1–2 minutes until fragrant, stirring constantly to prevent burning.
  4. Pour in the beef broth and add the thyme. Bring the mixture to a gentle simmer, uncovered, and cook for another 15–20 minutes, stirring occasionally. The broth should deepen in color and aroma.
  5. While the soup simmers, preheat your oven or toaster oven. Slice the baguette and toast until golden and crispy, about 8–10 minutes. Set aside.
  6. Ladle the hot soup into ovenproof bowls, then place a slice of toasted bread on top of each. Sprinkle generously with grated Gruyère cheese.
  7. Place the bowls on a baking sheet and broil in the oven until the cheese is bubbly, golden, and slightly crispy around the edges, about 2–3 minutes. Keep a close eye to prevent burning.
  8. Remove the bowls carefully from the oven, let rest for 2–3 minutes to cool slightly, then serve immediately, enjoying the bubbling, cheesy crust and rich onion broth.

Notes

Patience during caramelization is key. For a vegetarian version, substitute vegetable broth and dairy-free cheese options. To intensify flavor, add a splash of white wine during simmering.