I use this recipe and one other [Vinegar Piecrust] whenever I need pastry, whether it's for Apple Pie, Chicken Pot Pie or Meat pies. It never lets me down. The trick is to mix it just until it holds together. Over-mixing makes any pastry tough. I usually have to use a little bit more ice water than called for, but I add it sparingly.....
Flaky Pastry for a Two Crust Pie
Mix 2 cups of flour with 1 tsp salt.
Cut in 3/4 cup shortening [I use Crisco]until the mixture resembles coarse crumbs.
Sprinkle 5-6 Tblsps cold water, a Tblsp at a time, into the mixture, stirring lightly with a fork until pastry is just moist enough to hold together. Shape into a slightly flattened ball and chill until needed.
For a One Crust Pie use 1 cup of flour, 1/2 tsp salt, 1/4 cup plus 2 Tblsps shortening, 2-3 Tblsps ice water and proceed as above.