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French Onion Soup

This classic French onion soup is a celebration of simple ingredients transformed through patience and heat. By slowly caramelising the onions until they reach a deep, savoury sweetness, you create a complex base that pairs perfectly with the crisp, cheesy baguette topping. A splash of Calvados adds a subtle fruity brightness and depth to the rich broth, making each spoonful feel thoroughly indulgent and warming.

Ideal as an elegant starter for a dinner party or a comforting lunch on a chilly afternoon, this soup is a true bistro favourite. While traditionally made with beef stock, it remains a lighter option that focuses on high-quality cheese and crusty bread. Serve these individual ramekins bubbling hot from the oven to ensure your guests enjoy the perfect contrast of crunchy toast and melted Gruyère.

Continue reading below

Ingredients for French Onion Soup

  • 2 medium onions, finely chopped

  • 1 tablespoon unsalted butter

  • 1 tablespoon Calvados, Applejack, or other brandy

  • 950ml low-salt beef stock

  • Kosher salt and freshly ground black pepper

  • 4-8 1/2"-thick slices baguette, cut to fit ramekins

  • 120g grated Gruyère or raclette cheese

  • Four 275g ramekins

Preheat oven to 232°C. Cook onions in a 12" nonstick skillet over high heat, stirring constantly, until soft and caramelized, about 15 minutes. Add butter and toss onions to coat. Remove pan from heat and stir in Calvados. Return pan to heat and continue cooking until Calvados is absorbed, about 30 seconds. Add stock and bring to a simmer. Simmer until soup is reduced to 600g , about 5 minutes. Season soup to taste with salt and pepper.

Place ramekins on a rimmed baking sheet. Divide soup among ramekins. Top each ramekin with 1-2 slices of bread. Sprinkle 30g cheese over each. Transfer baking sheet with ramekins to oven and bake until cheese is bubbly and browned in spots, about 4 minutes.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 28 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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