In large bowl, stir together with fork (or pastry blender) flour, sugar and salt. Cut in shortening until crumbly. In small bowl, beat together water, vinegar and egg. Add to flour mixture and stir until all ingredients are moistened. Divide dough into 5 portions (4 if you use large pie plates). With hands shape each portion into a flat, round patty; wrap each patty in plastic wrap and chill at least 1/2 hour.
When you are ready to use the pie crust, lightly flour both sides of the patty and roll out on lightly floured board or pastry cloth.
Dough can be refrigerated for three days or frozen for weeks. If frozen, thaw and bring to room temperature before rolling out crust.