Onion soup gratinée

Forty minutes of onions and nothing else. The colour is the recipe — rush it and you get onion water.

• 800 g — onion
• 50 g — butter
• 20 g — plain flour
• 150 ml — dry white wine
• 1200 ml — brown stock
• 1 pc — bay leaf
• 1 pc — thyme
• 120 g — Gruyère, grated
• 6 g — salt
• 1 pinch — cracked black pepper

1. Melt the butter, add the onions and a good pinch of salt, and cover the pot for ten minutes so they release their water.
2. Take the lid off and cook uncovered for forty minutes on a medium-low heat, stirring every five. They go from white to gold to the colour of dark honey. Every one of those forty minutes is in the finished soup.
3. Stir in the flour, cook two minutes, then deglaze with the wine and reduce it almost away. Add the stock, bay and thyme and simmer thirty minutes.
4. Ladle into bowls, cover with Gruyère and put them under a hot grill until the cheese blisters. Bread is optional; the crust on the cheese is not.