Classic French Onion Soup

Caramelize the Onions (the heart of the flavor)
Slice all the onions into thin half-moons. In a large, heavy-bottomed pot, melt the butter with the olive oil over medium heat. Add all the onions at once, season generously with salt and pepper, and stir well with a wooden spoon. Cover and reduce heat to low. Cook for 1 hour, stirring every 15 minutes. The onions will shrink dramatically and turn golden, soft, and sweetly caramelized. This step is nearly effortless - just set a timer and relax.

Add Garlic & Flambé
Uncover, stir in the minced garlic, and cook for another 15 minutes until the onions are a deep, rich amber. Pour in the Cognac or Brandy and carefully ignite with a long match (flambe). The flames will flare up briefly and burn off the alcohol, leaving a luxurious, slightly nutty depth that turns the soup into something unforgettable. Stand back — it's safe, dramatic, and over in seconds.

Thicken & Simmer the Broth
Sprinkle the flour over the onions and stir for 2-3 minutes to cook out the raw taste. Gradually pour in the beef stock, scraping up all the golden bits from the bottom. Add the bay leaves, Worcestershire sauce, and thyme bundle (tie with kitchen twine for easy removal). Bring to a gentle boil, then reduce heat, cover, and simmer for 30 minutes - letting all the flavors meld into pure harmony.

Make the Crostini
While the soup simmers, preheat oven to 350°F / 180°C. Slice the baguette into ½-inch (1 cm) rounds, brush lightly with olive oil, sprinkle with salt and dried thyme, and toast on a baking sheet for 10 minutes until crisp and golden.

Broil with Cheese
Preheat oven to 475°F / 240°C. Remove bay leaves and thyme bundle. Ladle the hot soup into oven-safe bowls. Top each with a generous handful of grated Gruyère, place 2 toasted baguette slices on top, then cover with the remaining cheese. Bake for 12-15 minutes until the cheese is fully melted, golden, and bubbling. Let cool 2 minutes - then dig in.