Bring the Milk (2 cup) to a boil in a heavy medium-sized saucepan. Remove from heat and stir in the Green Tea Leaves (3 tablespoon). Cover and set aside to steep for 10 to 15 minutes.
Meanwhile, beat the Egg (2) and Granulated Sugar (2/3 cup) until thickened and pale yellow in a medium mixing bowl. Beat in the Corn Starch (1 tablespoon).
Place a fine mesh strainer over a 2 cup (or greater) glass measuring cup with a pouring lip. Pour the milk and tea leaves through the strainer, pressing on the solids to force the milk into the cup.
Add the milk in a steady stream to the egg mixture, beating until well combined. Pour back into the pan and heat over low heat, stirring constantly until custard begins to thicken.
Remove the custard from the heat and pour through a strainer into a large clean bowl - to remove any egg solids.
Allow the custard to cool slightly, then stir in the Heavy Cream (1 cup). Cover and refrigerate until well chilled - at least 2 hours or overnight.
Roughly chop the Pistachios (1/2 cup), and finely chop the Chocolate Chips (1/2 cup) or buzz through a mini food processor.
Stir the chilled custard then churn the ice cream according to your manufacturers instructions. When the ice cream begins to firm up, add the pistachios and chocolate chips. Continue to process for 5 to 10 minutes.
When finished the ice cream will be soft but ready to eat.