Classic French Onion Soup
Ingredients
- 1.5 kg (3.3 lbs) yellow onions, thinly sliced
- 60 g (4 tbsp) unsalted butter
- 1 tbsp olive oil
- 1 tsp sugar (optional, to assist caramelization)
- 2 cloves garlic, minced
- 120 ml (1/2 cup) dry white wine
- 30 ml (2 tbsp) Cognac or Brandy
- 1.5 L (6 cups) high-quality beef stock
- 3 sprigs fresh thyme
- 1 bay leaf
- 1 French baguette, cut into 2 cm (3/4 inch) slices
- 200 g (2 cups) Gruyère cheese, freshly grated
- Salt and freshly ground black pepper to taste
Like this recipe?
Save it to your personal cookbook and cook offline, anytime.
Instructions
- 1
Melt butter with olive oil in a heavy Dutch oven over medium heat. Add sliced onions, toss to coat, and cook uncovered for 10 minutes until softened.
- 2
Reduce heat to medium-low, add sugar and a pinch of salt, and cook for 40 to 50 minutes, stirring frequently, until the onions turn a deep mahogany color and are fully caramelized.
- 3
Add minced garlic and cook for 1 minute until fragrant. Pour in the Cognac and white wine, scraping up all the savory browned bits from the bottom of the pot, and simmer for 3 minutes.
- 4
Add beef stock, thyme sprigs, and bay leaf. Bring to a gentle simmer, then reduce heat to low, cover partially, and simmer gently for 20 minutes. Season with salt and pepper, then discard thyme stems and bay leaf.
- 5
Preheat the oven broiler. Toast baguette slices on a baking sheet at 200°C (400°F) for 6 to 8 minutes until golden and crisp.
- 6
Ladle hot soup into oven-safe ceramic bowls. Top each bowl with 1 or 2 toasted baguette slices and generously cover with grated Gruyère cheese.
- 7
Place bowls under the broiler for 3 to 4 minutes until the cheese is completely melted, bubbly, and golden brown. Serve hot immediately.
Notes
The fundamental key to authentic French onion soup is patience during the caramelization process; rushing onions on high heat will scorch them rather than release their natural sugars. Deglazing the pan with a dry white wine and finishing with a splash of Cognac builds the rich, aromatic complexity classic to Parisian bistros.
The Story Behind Classic French Onion Soup
Onion soups have been cherished since Roman times as a nourishing, affordable staple for working-class families due to the abundance of onions. The modern French iteration emerged in 18th-century Paris, famously served in the bustling markets of Les Halles to sustain night workers, merchants, and late-night revellers. According to popular legend, King Louis XV invented a prototype late one night in his hunting lodge using only onions, butter, and champagne. Over time, the addition of rich beef broth, toasted baguette croutons, and melted Gruyère transformed this humble dish into an international bistro classic.
More recipes you might like
Discover Classic French Onion Soup
Julia Child
Julia Child championed the rigorous technique of slow-caramelizing onions to build deep, savory flavor foundations in her seminal work *Mastering the Art of French Cooking*. She emphasized that true French onion soup relies entirely on gentle heat, high-quality stock, and real Gruyère cheese rather than artificial shortcuts.