In the bowl of a stand mixer, mix together the flours and salt. Add the cold butter and using the flat attachment, beat on medium low speed until the mixture resembles course crumbs and the butter pieces are no larger than pea size. Add the egg yolk and beat until the mixture just comes together. Sprinkle with ice water and mix with your hands until you can form the dough into a ball. Form into a ball and wrap in plastic wrap. Refrigerate for at least one hour. You may refrigerate for up to 2 days or freeze for up to 2 weeks.* Once chilled, sprinkle a countertop and the dough ball with a little flour. Using a rolling pin, start at the center of the dough ball and using light pressure, roll outward, rotating the dough ball as needed. Roll until approximately 12 inches in diameter.