Update: Further experiments have shown that other people in the house have decreased the size of Pi when I wasn't looking.
Step 1: Pistachio Nut Crust
2 sticks (16 tbsp) unsalted butter, chilled and cut into ½ inch pieces
½ cup finely ground pistachio nuts (preferably unsalted, if salted disregard the salt called for)
4 tbsp granulated sugar
1/2 teaspoon salt
4-6 tablespoons cold water
Finely chop the pistachios and then tap the bowl to separate the larger bits from the finer bits. Set aside the larger bits to use as a topping later. In a medium mixing bowl combine the nuts, flour, sugar and salt. Add butter and mix until mixture forms small chickpea-size pieces. Add cold water 1 tablespoon at a time, and mix until it is just moist enough to hold together. Form dough into a ball, divide it into two, wrap each ball with plastic wrap and flatten into discs. Refrigerate for at least one hour before rolling out and baking. Dough can be stored for 3 days in refrigerator or 2 weeks in freezer.