Rich, deeply caramelized onions simmered in beef stock, brandy, and thyme, then topped with crunchy sourdough croutons and melted Gruyère cheese—this French Onion Soup is the ultimate cozy comfort food. It takes time to slow-cook the onions to perfection, but the reward is a luxurious, savory broth topped with golden, bubbly cheese.

Ingredients

Serves: 4

• 4 tablespoons butter
• 5 large white onions, quartered and sliced
• ½ teaspoon salt
• 4 sprigs fresh thyme
• 60ml (2 oz) brandy or cognac
• 6 cups beef stock
• 1 tablespoon Worcestershire sauce
• 2 slices sourdough bread, torn into pieces
• 2 tablespoons olive oil
• 150g Swiss Gruyère, grated

How to Make French Onion Soup

1. Caramelize the Onions:
   • Place a large heavy-bottomed pot over medium heat.
   • Add the butter, and once melted, stir in the onions, salt, and thyme.
   • The pot will be full at first—this is normal!
   • Cook over medium to medium-low heat, stirring occasionally, for 45 minutes to 1 hour, until the onions are soft, jammy, and golden brown.
2. Prepare the Broth:
   • While the onions cook, heat the beef stock in a separate pot.
3. Toast the Sourdough Croutons:
   • Preheat the oven to 350°F (175°C).
   • Tear up the sourdough bread and place it on a baking sheet.
   • Drizzle with olive oil, toss, and bake for 8 minutes, tossing once, until golden and crisp.
   • Set aside.
4. Deglaze & Simmer:
   • Once the onions are golden brown, add the brandy and scrape up any browned bits from the bottom of the pot.
   • Cook for 30 seconds until the alcohol has evaporated.
   • Pour in the beef stock and Worcestershire sauce.
   • Bring to a simmer and cook for 5 minutes.
5. Assemble & Broil:
   • Preheat the broiler to high.
   • Place oven-safe soup bowls on a baking sheet.
   • Fill each bowl ¾ full with soup, top with a handful of sourdough croutons, and sprinkle generously with Gruyère cheese.
   • Transfer the baking sheet to the oven and broil until the cheese is bubbly and golden.
6. Serve Immediately!

Tips & Variations

• Caramelization is key! Take your time with the onions—the longer they cook, the better the flavor.
• Make it vegetarian: Swap beef stock for mushroom or vegetable broth.
• Try a different cheese: Gruyère is traditional, but Comté, Emmental, or aged Cheddar also work beautifully.
• Make ahead: The soup base can be made in advance and stored in the fridge for up to 3 days—just reheat and assemble before serving.

FAQ

Can I freeze French onion soup?
Yes! Freeze the broth without the croutons and cheese for up to 3 months. Reheat and broil fresh before serving.

What’s the best way to serve this?
Serve piping hot, with extra croutons and cheese on the side for the ultimate experience.

Can I use red onions instead?
Yes, but they’ll make the soup slightly sweeter. White or yellow onions are the best choice for the classic deep flavor.

And that’s it for this French Onion Soup! If you make it, tag me on Pinterest or Instagram—I’d love to see your creations! For more comforting soups, check out my Soups & Stews collection here.

French Onion Soup

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• Author: Andrea Buckett

Ingredients

4 tablespoons butter

5 large white onions, quartered and sliced

1/2 teaspoon salt

4 sprigs of thyme

60ml (2 oz) brandy or cognac

6 cups beef stock

1 tablespoon Worcestershire sauce

2 slices of sourdough bread

2 tablespoons olive oil

150g Swiss Gruyere, grated

Instructions

1. Place a large heavy bottomed pot on a burner set to medium heat. Add the butter. Once melted add all of the onions, salt and thyme. Stir to combine. The pot will be full, that’s okay. Cook over medium heat to medium low, stirring occasionally until the onions are soft and jammy and starting to turn golden brown. This will take 45min to an hour.

2. In the meantime, heat up some beef stock

3. Tear up the sourdough bread and place on a baking sheet. Drizzle with olive oil and toss. Bake in a 350°F oven for 8 minutes, tossing once until toasted. Remove from the oven and set aside.

4. Once the onions are golden brown add the brandy and scrape any browned bits from the bottom of the pot. Cook for 30 seconds until the brandy has evaporated. Pour in the beef stock and Worcestershire. Bring to a simmer and cook for 5 minutes.

5. Preheat the broiler too high. Place the soup bowls on a baking sheet. Fill ¾ of the way with soup, top with a handful of sourdough croutons and top with a handful of cheese.

6. Transfer the baking sheet to the oven and broil until the cheese is bubbly.

Serve immediately