Onions (6 large): Thinly sliced, they form the base of the soup.
Butter (50g / ¼ cup): Used to sauté the onions to a golden caramelization.
Olive oil (2 tbsp): This helps prevent the butter from burning during the cooking process.
Beef stock (1.5 liters / 6 cups): Provides the rich, savory base of the soup.
White wine (150ml / ½ cup): Adds acidity and depth of flavor.
Thyme (1 tsp): Fresh or dried thyme adds an aromatic herbal note.
Bay leaf (1): Enhances the flavor of the soup as it simmers.
Baguette slices (4-6): Toasted and topped with cheese to serve.
Gruyère cheese (100g / 3.5 oz): Grated, for topping the toasted baguette.
Salt and pepper: To taste, for seasoning.
Instructions
Sauté the onions: In a large soup pot, melt the butter and olive oil over medium heat. Add the sliced onions and cook for 20-30 minutes, stirring occasionally, until they are soft and caramelized. They should turn a deep golden brown color.
Add the wine and deglaze: Pour in the white wine, scraping the bottom of the pot to release any browned bits. Let the wine simmer for 5 minutes to reduce slightly.
Add the stock and herbs: Stir in the beef stock, thyme, and bay leaf. Bring the soup to a boil, then reduce the heat to low and let it simmer for 20-30 minutes to allow the flavors to develop.
Season and taste: Remove the bay leaf and taste the soup. Season with salt and pepper as needed.
Prepare the croutons: While the soup simmers, toast the baguette slices until golden. Top each slice with grated Gruyère cheese and place under the grill (broiler) until the cheese is melted and bubbling.
Serve: Ladle the soup into bowls and top with the cheesy croutons. Serve hot and enjoy!
Expert Tips
Caramelize the onions slowly: Take your time caramelizing the onions—this step is key to developing the deep, rich flavor of the soup.
Deglaze the pan: Use the wine to deglaze the pan, scraping up the flavorful bits stuck to the bottom.
Use good-quality stock: A rich, flavorful beef stock will make a big difference in the depth of the soup.
Make it ahead: French onion soup often tastes even better the next day, as the flavors have more time to meld.
Cheese variation: If Gruyère is not available, you can use Emmental or Comté for the croutons.
