3 1/2 tablespoons cold vegetable shortening, cut into small pieces
3 tablespoons cold unsalted butter, cut into 1/2-inch pieces
3 tablespoons ice water
In a food processor, blend the flour with the sugar and salt. Add the shortening and butter and pulse until the mixture resembles coarse meal. Drizzle in the ice water and pulse until the dough forms small clumps. Turn the dough onto a lightly floured work surface and press it out with the heel of your hand. Gather the dough together and flatten it into a 4-inch disk. Wrap in plastic wrap and refrigerate for at least 1 hour.
On a lightly floured surface, roll out the dough to a 12-inch round. Transfer to a 9-inch glass pie plate. Trim any overhanging dough and flute the edges. Prick the bottom of the shell all over with a fork and freeze until firm, about 20 minutes.
Preheat the oven to 450°. Line the frozen pie shell with foil and fill with pie weights or dry beans. bake for 20 to 25 minutes, or until the edges are slightly golden. remove the foil and bake for 5 to 8 minutes more, or until the center loses its raw look. The shell should be a little light; it will be baked again. Let cool on a rack before adding the filling.
The dough can be prepared through Step 1 and refrigerated overnight, or prepared through step 2 and frozen for up to 1 month.