The pie dough may be made one day ahead and refrigerated, well wrapped in plastic, or frozen up to one month.
Place the flour, salt, and sugar in the bowl of a food processor, and process for a few seconds to combine. Add the butter pieces to the flour mixture, and process until the mixture resembles coarse meal, about 10 seconds. Add the ice water in a slow, steady stream, pouring it through the feed tube with the machine running, just until the dough holds together. Do not process for more than 30 seconds.
Turn the dough out onto a work surface. Divide into 2 equal pieces, and place on 2 separate sheets of plastic wrap. Flatten, and form 2 disks. Wrap, and refrigerate at least 1 hour before using.