Put the egg yolks into a mixing bowl with 25 g (1 oz) of the caster sugar and whisk very lightly together.
Put the cream into a saucepan with the vanilla bean and heat gently until it’s almost boiling.
Gently whisk the cream into the egg yolks.
Set the bowl of custard over a saucepan of hot water and cook, stirring until the custard becomes thick.
Immediately train the custard through nylon sieve into a heatproof serving dish, about 20 cm (8 inch) diameter and 2.5 cm (1 inch) deep.
Allow the custard to cool, then chill in the refigerator, preferable overnight, until set.
2 hours before serving, remove the custard from the refrigerator and sprinkle the surface with the remaining caster sugar, making sure that it forms a single layer.
Allow to stand for about 10minutes, then cook under a hot grill until the sugar dissolves and turns into a golden caramel colour.
