
Put the pistachios in a food processor and blitz to a fine crumb. Be careful not to over blitz them or it’ll turn to butter. Set aside.
Put the sugar and water in a saucepan and bring to a boil until the sugar has dissolved then turn off the heat. Add the pistachio cream and whisk it into the sugar syrup until fully melted.
Let the pistachio mixture cool completely then add the chopped pistachios.
Transfer the mixture into a freezer-proof container and place in the freezer for 6 hours to overnight until frozen.
When ready to serve, remove the granita from the freezer and break it into medium-sized chunks (you may need to let the granita sit a room temperature for 5-10 minutes if it’s difficult to break).
Blitz the chunks in a food processor until smooth and slushy then serve.
Tip - just blitz the amount of granita you are going to serve and put the rest back in the freezer.