I've used the creme brulee instructions from the gbc website to make the custard.
Measure sugar into a large mixing bowl and set aside
Pour the cream and vanilla into a saucepan and slowly heat to 60c (or until just steaming)
While the cream is heating, add the yolks to the sugar whisikng immediatly as the yolks touch the sugar until pale and thick.
Pour a small amount of the warmed cream into the yolk mix and stir in, then pour the rest of the cream into the eggs and mix well with a heat proof spatula.
Pour all the mixture back into the saucepan over a low heat and keep stirring until the mixture reaches 75c or you can trace a finger through the cream on the spatular and a clear line is left.
Cut the grapes in half and arrange in a fireproof dish.
Pour over the custard.
Sprinkle over granulated sugar.
Blowtorch the top carefully.
Sprinkle with a layer of icing sugar.
Leave to cool so the top becomes nice and crunchy.