French Onion Soup Gratin
soupsIntermediate

French Onion Soup Gratin

The quintessential French bistro classic — deeply caramelised onions in a rich, glossy broth, topped with a toasted baguette crouton and a bubbling, golden Gruyère gratin.

1 hr 30 min4 servings

Ingredients

  • 1.2 kg (2.6 lbs) yellow onions, thinly sliced
  • 60 g (4 tbsp) unsalted butter
  • 2 tbsp olive oil
  • 1 tsp sugar
  • 3 cloves garlic, minced
  • 200 ml (¾ cup) dry white wine or dry sherry
  • 1 litre (4 cups) good-quality beef stock
  • 1 tbsp fresh thyme leaves
  • 2 bay leaves
  • Salt and black pepper
  • 8 slices baguette, toasted
  • 150 g (1½ cups) Gruyère cheese, grated
  • 30 g (⅓ cup) Parmesan, grated
French Onion Soup Gratin

Instructions

  1. 1

    Melt the butter and olive oil in a large, heavy pot over medium heat. Add the onions and sugar. Cook, stirring occasionally, for 45–55 minutes until the onions are deeply caramelised and a rich mahogany colour. Do not rush this step — it is the foundation of the soup.

  2. 2

    Add the garlic and thyme and stir for 1 minute. Pour in the wine and let it bubble for 3 minutes, scraping up any browned bits.

  3. 3

    Add the stock and bay leaves. Bring to a simmer and cook for 20 minutes. Remove the bay leaves. Season generously with salt and pepper.

  4. 4

    Preheat the oven grill (broiler) to high. Ladle the soup into 4 oven-safe bowls placed on a baking tray.

  5. 5

    Float 2 toasted baguette slices on top of each bowl of soup.

  6. 6

    Mix the Gruyère and Parmesan together. Pile generously over the croutons, covering the surface completely. Grill (broil) for 3–5 minutes until the cheese is bubbling, golden, and beginning to char at the edges. Serve immediately — the bowls will be very hot.

Frenchsoupsvegetarian

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