1. Put milk and sugar into a large heavy bottomed pan and boil until reduced to a third and mixture is thick and creamy. Add cardamom, pistachio slices and saffron. Cook for 5 minutes. Cool to room temperature. Spoon the mixture into 4 moulds. Tightly cover the moulds with foil and freeze overnight.
Time: Preparation: 15 minutes plus 6-7 hours for setting. Cooking: 30 minutes
To Serve: Wrap moulds in a warm towel for 5 minutes then invert onto individual serving plates.