Chop the white chocolate into small pieces and place in a glass bowl together with the cream, finely grated rind of half an orange and the rum - place over a pan of boiling water and heat for 3 mins stirring constantly

Place the mixture in the fridge for 2 hours then whisk everything until the mixture becomes light and airy

Separate the egg and beat the egg white until stiff then add the sugar and juice of half a lemon

Finally mix everything together and chill thoroughly before serving