The Delicious Crescent

0 Prep the pistachios: Boil 4 cups of water and add 2 cups of shelled pistachios. Simmer for [timer minutes=2]2 minutes[/timer], then drain and rinse with cold water. Cool the pistachios and remove the skins by rubbing them between kitchen towels.
1 Blend the pistachios: In a high-speed blender (Vitamix), combine 2 cups pistachios and 2 cups milk. Blend until smooth, about [timer minutes=2]2 minutes[/timer]. Alternatively, finely grind the pistachios using a food processor. Cover and refrigerate overnight.
2 Strain the mixture: Pour the chilled pistachio-milk mixture through cheesecloth or a nut bag to remove any solids. Stir occasionally to dislodge solids lining the cloth. I did not strain the mixture as my Vitamix blends the nuts and milk into a smooth and thick paste.
3 Thicken the nut milk: Do this only if nut milk is not thick like a flowing custard. In a large saucepan, heat the pistachio-milk over medium-high, stirring constantly. Do not let it boil. Dissolve corn starch in ½ cup plain milk until smooth. Lower the heat and whisk in the corn starch-milk mixture. Simmer until the mixture reaches a thin custard consistency or coats the back of a spoon, about [timer minutes=6]6 minutes[/timer]. Remove from heat and cool on an ice bath.
4 Add other ingredients: Whisk in sugar, remaining milk (if not used for thickening), salt, and pistachio extract until well combined. Then stir in heavy cream. Instead of flavor extract, I used a drop of almond extract plus 2 tablespoons of La Tourangelle brand pistachio oil.
5 Chill the mixture: Refrigerate the mixture for several hours or overnight, or use an ice bath for faster chilling.
6 Freeze the gelato: Follow the ice cream maker's instructions to freeze the mixture. Optionally, add the coarsely ground pistachios when the gelato starts to set.