Sift flour and salt into a large mixing bowl. Cut butter into 12 pieces and rub into dry ingredients until the mixture resembles a coarse meal with some pea-size pieces. Sprinkle water over mixture, one tablespoon at a time and knead lightly just until dough forms. Form dough into a ball. Cut in half and press each into a disc shape. Wrap each disc in waxed paper or plastic wrap and refrigerate for 30 minutes before rolling.