Mix shortening, salt and boiling water in a large bowl. Whip with a fork until fluffy. Add the flour all at once. Stir until it leaves the side of the bowl. Roll between two sheets of wax paper. Makes enough for a two-crust pie. If using for two one-crust pies, bake at 375 10-12 minutes or until light brown before adding filling. This also freezes well if made up ahead, if you like to have pie shells on hand for one-crust pies.