How to Make It
Stir together milk, raw pistachios, and 1/2 cup of the sugar in a medium saucepan; bring to a simmer over medium, stirring occasionally to dissolve sugar. Reduce heat to medium-low; cook, undisturbed, until pistachios soften, about 15 minutes. Pour mixture into a high-powered blender. Secure lid on blender, and remove center piece to allow steam to escape. Place a clean towel over opening. Process until smooth, about 1 minute.
Whisk together egg yolks and remaining 1/2 cup sugar in a medium bowl. Gradually add 1 cup of the warm pistachio puree, whisking constantly. Return remaining pistachio puree in blender to saucepan; whisk in egg yolk mixture, whipping cream, salt, and vanilla. Cook over medium, whisking often, until mixture coats the back of a spoon, 8 to 10 minutes. Pour mixture through a fine mesh strainer into a large bowl; whisk in food coloring. Cover loosely with plastic wrap. Chill until cold, at least 2 hours or up to overnight (or 8 hours).
Stir chopped pistachios into cold cream mixture. Pour mixture into frozen freezer bowl of a 2-quart electric ice-cream maker, and proceed according to manufacturer’s instructions. (Instructions and times may vary.) Transfer to a shallow container; press parchment paper against surface. Cover with plastic wrap (or seal lid on container), and freeze until frozen, at least 4 hours or up to overnight (or 8 hours). Store in an airtight container in freezer up to 2 weeks.