In a small mixer bowl, combine flour and salt. Add shortening. Beat with an electric mixer on low speed till pieces are the size of small peas. (This should take 15-20 sec.) Add water all at once: beat on low speed just till moistened (10-15 sec.). Form dough into a ball. Divide into 2 balls.
For single crust, turn 1 ball of pastry onto floured surface. Roll dough forming a 12 inch circle. Ease pastry into 9 inch pie plate. Trim edge of plate. Fold pastry under: flute edges. If pastry is to be baked without filling, prick bottom and sides. Repeat with remaining. Bake in 450°F oven 10-12 minutes.
For double crust, prepare 1 dough ball except trim crust even with pie plate. Roll out remaining ball: cut slits for escape of stream. Place over desired filling. Continue as above.