Maison Ardoise · Starters

Bistro French Onion Soup with Gruyère Toasts

Name: Bistro French Onion Soup with Gruyère Toasts
Total time: 105 min
Yield: 4 servings
Ingredients: 1200 g Yellow onions; 40 g Unsalted butter; 1 tbsp Olive oil; 1 tsp Salt; 0.5 tsp Granulated sugar; 2 clove Garlic; 1 tbsp All-purpose flour; 125 ml Dry white wine; 1.2 L Low-sodium beef stock; 4 sprig Fresh thyme; 1 whole Bay leaf; 1 tsp Sherry vinegar or brandy, optional; 0.5 tsp Black pepper; 8 slice Baguette; 160 g Gruyère cheese

A deep, sweet and savoury soup built on onions cooked slowly until they turn mahogany, deglazed with white wine and simmered in beef stock with thyme, then crowned with toasted baguette and bubbling, browned Gruyère.

105 minutes · Medium · 4 servings

Original house recipe · Not yet kitchen-tested

Ingredients

Yellow onions1200 g
Unsalted butter40 g
Olive oil1 tbsp
Salt1 tsp
Granulated sugar0.5 tsp
Garlic2 clove
All-purpose flour1 tbsp
Dry white wine125 ml
Low-sodium beef stock1.2 L
Fresh thyme4 sprig
Bay leaf1 whole
Sherry vinegar or brandy, optional1 tsp
Black pepper0.5 tsp
Baguette8 slice
Gruyère cheese160 g

Quantities describe recipe usage, not package sizes.

Allergen notes

Wheat (flour, baguette), milk (butter, Gruyère) and sulphites (wine). Check beef stock labels for celery and other allergens.

Method

Slice the onions

Halve the onions through the root, peel them and slice into thin half-moons about 3 mm thick. It looks like a mountain, but they cook down to about a quarter of the volume.

Caramelise slowly

Melt the butter with the oil in a large, heavy pot over medium heat. Add the onions, salt and sugar and stir to coat. Cook for 50–60 minutes, stirring every 5 minutes and more often towards the end, lowering the heat if they start to catch. When brown bits stick to the bottom, add 2 tbsp of water and scrape them up. They are ready when soft, jammy and a deep golden brown.

Build the soup

Stir in the finely chopped garlic for 1 minute, then the flour for 1 minute. Pour in the wine and scrape the bottom of the pot clean. Simmer for 2 minutes, then add the stock, thyme and bay leaf. Simmer gently, partly covered, for 25 minutes. Remove the thyme stems and bay leaf, add the vinegar or brandy if using, and season with pepper and more salt to taste.

Toast the bread

Meanwhile, heat the oven to 200°C (400°F). Lay the baguette slices on a baking tray and toast for 6–8 minutes, until dry and lightly golden. Coarsely grate the Gruyère.

Gratinate and serve

Turn the oven to its broiler (grill) setting. Set 4 ovenproof soup bowls on a baking tray and ladle in the hot soup. Float 2 toasts on each and pile the cheese generously over the top, letting it drape to the rim. Broil 15 cm from the element for 2–4 minutes, watching closely, until the cheese is bubbling and browned in spots. Warn everyone that the bowls are very hot.

Do not rush the onions with high heat: they need the full hour to develop real sweetness. The soup base (without the toasts and cheese) keeps in the fridge for 3 days and tastes even better made ahead.

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