In a large bowl, combine the flour, sugar and salt; cut in shortening until crumbly. Whisk the egg, water and vinegar; gradually add to flour mixture, tossing with a fork until dough forms a ball. Divide into four portions. Cover and refrigerate for at least 1 hour.
On a lightly floured surface, roll out each portion of dough to fit a 9-in. pie plate. Transfer pastry to pie plates. Trim each pastry to 1/2 in. beyond edge of plate; flute edges. Fill or bake shells according to recipe directions.