To make the pistachio cream, toast the pistachios under a grill for 1-2 minutes, shaking to make sure they don’t burn. Grind the nuts to a paste using a mortar and pestle or a food processor. Pour the milk into a saucepan and heat slowly until just at boiling point. Meanwhile, cream together the egg yolks and sugar until pale. Pour the milk onto the yolks, mixing well.