Combine the flour, salt, and sugar in food processor. Add butter; process until mixture resembles coarse meal, about 8 to 10 seconds. (For hand method, place dry ingredients in large bowl. Add butter; blend with pastry cutter until mixture resembles coarse meal.)
Add ice water in a slow steady stream through feed tube of food processor with machine running, until the dough holds together for no longer than 30 seconds. (For hand method, mix dough with a wooden spoon, adding water until dough just holds together.)
Turn dough onto piece of plastic wrap. Press into a disk, and. wrap in plastic wrap. Refrigerate at least 1 hour. May be frozen, double wrapped in plastic, for several months.