Ingredients
2cupsall purpose flour
2tbspsugar
½tspsalt
3tbspcocoa
12tbspcold unsalted butter
½tspvanilla extract,optional
1½cupshalf and half
3large egg yolks
¾cupdark brown sugar
1tbspcornstarch
2tbspcocoa powder
1tspsalt
4ozbittersweet chocolate,finely chopped
3tbspunsalted butter
1½tspvanilla extract
¾cupheavy cream
5tsppistachio paste
2tspsugar
1tbsppistachios,finely chopped
chocolate shavings,optional for garnish
Preparation
Stir together flour, sugar, salt, and cocoa in a large bowl. Use a pastry blender or a fork to cut in butter until the mixture resembles coarse meal with pea-size bits of butter throughout. (Or combine dry ingredients in a food processor, then pulse in butter.)
Drizzle in 1 to 2 tablespoons of ice water at a time (up to 6 tablespoons total), tossing after each addition, and using only enough water to make dough clump together when squeezed. Add vanilla (if using).
Pat dough into a 4-inch circle, tightly cover with plastic wrap or parchment, and chill for 30 minutes or up to 2 days (or freeze for up to 3 months).
Preheat oven to 400 degrees F. Cut cold dough into 4 pieces and grate into a 9-inch pie plate using large holes of a box grater; work quickly to keep dough cold.
Press dough into bottom, sides, and along the rim of pan to uniform thickness. Trim excess dough; crimp edges. Chill 20 minutes.
Line shell with parchment paper and fill with rice or pie weights. Bake 10 to 12 minutes; remove rice and paper and bake until crust is cooked through, 8 to 10 more minutes. Cool on a rack.
Whisk half-and-half, yolks, brown sugar, cornstarch, cocoa, and salt in a medium saucepan. Cook over medium-high heat, stirring constantly, until it thickens and bubbles. Cook 1 minute more; remove from heat.
Stir in bittersweet chocolate, butter, and vanilla. Pour into pie shell; cool completely. Transfer to refrigerator to set, at least 2 hours or up to 2 days.
When serving, make a topping by beating heavy cream, pistachio paste, and sugar (if using) in a cold bowl to soft peaks. Sprinkle pie with pistachios and chocolate shavings (if using); add a dollop of pistachio cream to each slice.
