Pastry Dough - cold unsalted butter

Method

• Cut butter into 1/2-inch cubes.
• Blend together flour, butter, shortening, and salt in a bowl with your fingertips or a pastry blender until most of mixture resembles coarse meal, with rest in small (roughly pea-size) lumps.
• Drizzle 2 tablespoons ice water evenly over and gently stir with a fork until incorporated.
• Pulse together flour, butter, shortening, and salt in a food processor until most of mixture resembles coarse meal, with rest in small (roughly pea-size) lumps.
• Add 2 tablespoons ice water and pulse 2 or 3 times, or just until incorporated.
• Gently squeeze a small handful: It should hold together without crumbling apart.
• If it doesn't, add more ice water, 1 tablespoon at a time, stirring or pulsing 2 or 3 times after each addition until incorporated (keep testing).
• (If you overwork mixture or add too much water, pastry will be tough.)
• Turn out onto a work surface and divide into 4 portions.
• With heel of your hand, smear each portion once in a forward motion to help distribute fat.
• Gather dough together and form it, rotating it on work surface, into a disk.
• Chill, wrapped in plastic wrap, until firm, at least 1 hour.