Process the flour, salt and sugar in a food processor until combined. Add the shortening and process until the mixture has the texture of coarse sand, about 10 seconds. Scatter the butter pieces over the flour mixture; cut the butter into the flour until the mixture is pale yellow and
resembles coarse crumbs, with butter bits no larger than small peas, about ten 1-second pulses. Turn the mixture into a medium bowl.
Sprinkle 6 tablespoons of the ice water over the mixture. With a rubber spatula, use a folding motion to mix. Press down on the dough with the broad side of the spatula until the dough sticks together, adding up to 2 tablespoons more ice water if the dough will not come together. Divide the dough into 2 balls and flatten each into a 4- inch disk. Wrap each in plastic and refrigerate at least 1 hour, or up to 2 days, before rolling.
