Yield: 4 servings. Put the egg yolks, milk an 50g sugar in the top of a double boiler, or heavy based saucepan. Cook gently for 15 minutes, stirring, until the mixture thickens and coats the back of a spoon. Stir in the vanilla. Divide the custard between individual dishes. Cover and refrigerate for 1 hour. Whisk the egg white until stiff. Add 2 tablespoons sugar and whisk again until the sugar is dissolved. Pour water into a large frying pan to a depth of 2 cm. Bring to a gentle simmer. Shape the meringue into ovals, using 2 tablespoons as moulds. Carefully slide into the water and poach gently for about 3 minutes until set, turning once. Remove the meringues with a slotted spoon, drain for a minute on absorbent kitchen paper and spoon on to the custard in the dishes. Put the remaining sugar into a heavy-based saucepan and cook, stirring, for about 3 minutes, until it forms a golden syrup. Remove from the heat and leave for 2 minutes to cool slightly, then drizzle a little of the warm syrup over each meringue.