Whisk flour, salt, and optional sugar in a wide bowl. Add cold cubed butter and toss so the pieces are coated in flour.
Cut butter into the flour with a pastry blender until most pieces are pea-size with a few slightly larger flat flakes.
Drizzle in 6 tablespoons ice water and toss with a fork. Add more a teaspoon at a time only until a squeezed handful holds together.
Turn onto the counter and press into two discs without kneading. Wrap and refrigerate at least 1 hour so flour hydrates and butter firms.
Roll one disc from the center outward into a 12-inch circle on a lightly floured surface, rotating frequently. Patch edge cracks rather than adding excess water.
Drape into a 9-inch plate without stretching, trim to a 1-inch overhang, and fold under to crimp. Chill 20 minutes before filling or blind baking.
For an empty baked shell, heat oven to 375°F (190°C), line with parchment, and fill with weights. Bake 20 minutes, then remove weights and paper.
Bake another 12–18 minutes until golden and dry. For filled pies, follow that recipe instead; an unfilled second disc stays wrapped and chilled until needed.
