Saffron & Pistachio Ice Cream (Bastani Irani)

INGREDIENTS:
2 Tbsp powdered sahlab or cornstarch
4 cups milk
1 cup sugar
1/2 tsp ground mastic (Arabic gum)
1/4 tsp ground saffron dissolved in 3 Tbsp rose water
1/2 cup whipping cream
2 Tbsp slivered pistachios for decoration

DIRECTIONS:
1. Dissolve the sahlab or cornstarch in 1 cup cold milk. Mix very well until the mixture is quite smooth.
2. In a large saucepan, stir the rest of the milk and sugar together and bring to a boil over medium heat.
3. Add the sahlab mixture and mastic to the warm milk in the saucepan. Simmer over medium heat, stirring constantly, until the mixture thickens. At this stage, the mixture should be slightly elastic. Remove the pan from the heat.
4. Add saffron-rose water. Mix well. Allow to cool for 2 hours. Pour the entire mixture into an ice-cream machine.
5. Follow your ice-cream machine's directions for making ice cream.
6. Pour a thin layer of whipping cream into a flat plate and place it in the freezer until a 1/4 inch frozen creamy crust forms. Remove the crust from the freezer, let it stand for 2 minutes, then break off 1/2 inch pieces of the crust and mix them with the finished ice cream.
7. Serve ice cream in bowls; spring the top with ground pistachios.

Variation: You may simply use 1 pint vanilla ice cream. Simply add frozen cream pieces, saffron-rose water, and slivered pistachios. Mix well.