Crush the chocolate and melt it in a water bath. Let cool down a bit, then stir in the yogurt. Soak and dissolve the gelatine according to the instructions. Stir three tablespoons of the chocolate yoghurt mixture into the gelatine. Then pull this mixture back into the rest of the chocolate yoghurt mixture. Fold in the whipped cream. Flavor with brandy if you like. Chill for an hour before consumption.