• 30 scallops
• 450 g/1 lb leeks
• 225 g/8 oz unsalted butter
• 450 ml/¾ pint fish stock
• 150 ml/¼ pint dry vermouth
• 175 ml/6 fl oz double cream
• 6 scallop-shaped pastry shells
• Salt and freshly ground pepper

Trim and wash the leeks, cut about 25 g/l oz of them into fine strips 4 cm/1½ inches long and set to one side. Roughly cut up the rest into quite small pieces. Using 15 g/½ oz of the butter, sweat the leeks in a covered pan over a low heat until cooked. When cooked, drain them well and then purée them in a blender or food processor until smooth.

Shell, trim and wash the scallops; dry well. Leave the roes attached and slice the white meat across into 2 rounds, leaving the whole roe attached to one round. Butter a pan, add the scallops, fish stock and vermouth, and cover with buttered paper or foil. Poach gently for 1 minute. Drain the scallops, cover and leave in a warm place. Bring the stock back to the boil, plunge in the strips of leek for about 15 seconds, remove and keep warm. Reduce the stock over a high heat until syrupy.

Add 50 ml/2 fl oz of the cream to the leek pureé, check the seasoning and gently reheat. Add the remaining cream to the sauce and reboil, remove the pan from the heat and whisk in the butter in small amounts until it has all melted.