1 cup (2 sticks) chilled unsalted butter, cut in pieces
1/4 to 1/2 cup ice water
Place the flour, salt, and sugar in the bowl of a food processor, and process for a few seconds to combine. Add the butter, and process until the mixture resembles coarse meal, about 10 seconds. With the machine running, add the ice water in a slow, steady stream, through the feed tube, just until the dough holds together. Do not process for more than 30 seconds.
Turn the dough out onto a work surface. Divide in two. Place each half on a sheet of plastic wrap. Flatten, and form two rectangles. Wrap, and refrigerate at least 1 hour before using.