In a food processor, combine flour and salt. Add shortening; cover and pulse until mixture resembles coarse crumbs. While processing, gradually add soda until dough forms a ball. Cover and refrigerate for 1 hour or until easy to handle.
For two single crust pies, on a lightly floured surface, roll out half of the pastry to fit a 9-in. pie plate. Transfer pastry to pie plate. Trim pastry to 1/2 in. beyond edge of plate; flute edges. Repeat with remaining pastry. Fill or bake according to recipe directions.
For a double crust pie, divide dough in half so that one portion is slightly larger than the other. On a lightly floured surface, roll out larger portion to fit a 9-in. pie plate. Transfer pastry to pie plate. Trim pastry to 1 in. beyond edge of plate. Add filling.
Roll out remaining pastry to fit top of pie; place over filling. Trim, seal and flute edges. Cut slits in pastry. Bake according to recipe directions.
Editor’s Note: To make without a food processor, in a large bowl, combine flour and salt; cut in the shortening until crumbly. Gradually add soda, tossing with a fork until dough forms a ball. Proceed as directed.