In a medium bowl, stir together flour and salt. Cut in shortening with a pastry cutter until mixture looks like crumbs.
Add 3 tablespoons of ice-cold water to the crumb mixture. With a fork, gently toss. Continue adding water, one tablespoon at a time, until the dough is formed and moves around the bowl (this is a fine art). You don’t want the dough too dry or too wet. Also, the less you “work” the dough, the flakier it will be.
Divide the dough into 2 even disks. Wrap each disk in a damp paper towel and place into a zip-lock bag. Place the bag into the refrigerator until you are ready to use.
For a single-crust pastry: reduce flour to 1 1/2 cups, salt to 1/2 teaspoon and shortening to 6 tablespoons; start with 2 tablespoons ice-water and continue adding as needed.