Make the parfait by melting the chocolate in a saucepan which is standing in hot water.
Whip the eggs and sugar until light and fluffy. To this, quickly add the melted chocolate and then fold in the half-whipped cream and then lastly the rum. Pour into a tin foil lined terrine mould. Place into deep freeze for 24 hours.
Make the sauce by whisking the egg yolks and sugar together