Bastani sonnati

Step 1: The day before, pour the ½ cup double cream onto a small tray lined with baking paper in a layer about 3 mm thick and freeze until solid.

Step 2: Steep the ground ½ tsp saffron threads in the 2 tbsp hot water for 15 minutes until deep orange.

Step 3: Heat the 2 ½ cups whole milk and 1 cup double cream in a saucepan over a medium heat until steaming with small bubbles at the edge. If using 1 tsp salep powder, whisk it into the cold milk first so it doesn't lump.

Step 4: Whisk the 5 egg yolks, 6 oz caster sugar and 1 tbsp cornflour in a bowl until pale. Pour in the hot milk in a thin stream, whisking all the time, then return everything to the pan.

Step 5: Cook over a low heat, stirring and scraping the bottom, for 6–8 minutes until the custard thickens enough to coat the back of a spoon and reaches 180°F. Common mistake: letting it boil, which scrambles the yolks into grains.

Step 6: Strain into a bowl, stir in the saffron liquid and 3 tbsp rosewater, and cool. Cover and chill for at least 4 hours, or overnight.

Step 7: Churn in an ice-cream machine until thick and soft-set. Without a machine, freeze it in a shallow box and beat it hard with a fork every 45 minutes, four times, to break up the ice crystals.

Step 8: Break the frozen cream into small shards and fold them and the 2 ½ oz pistachios through the ice cream quickly, so the shards stay whole. Freeze for 2 hours until firm enough to scoop. Soften for 10 minutes in the fridge before serving.