PASTRY FOR DOUBLE-CRUST PIE: In a mixing bowl, stir together flour and salt. Using a pastry blender, cut in shortening till pieces are the size of small peas. Sprinkle 1 tablespoon of the cold water over part of the mixture; gently toss with a fork. Push to side of bowl. Repeat, using 1 tablespoon of water at a time, til all is moistened. Divide in half, form each half into a ball. PASTRY FOR SINGLE-CRUST PIE: Follow the directions for Pastry for Double-Crust Pie.