Prep the butter: Cut butter into cubes and return to refrigerator while you prepare the dry ingredients. Fill a glass with ice water and set aside.

Mix dry ingredients: In a food processor, pulse together the flour, xanthan gum (if using), sugar (if using), and salt until combined.

Cut in butter: Add half the cold butter cubes. Pulse 8-10 times until the mixture resembles coarse meal. Add remaining butter and pulse 5-6 times until you have pea-sized pieces of butter throughout.

Add liquid: With the processor running, drizzle in 8 tablespoons of ice water (leave the ice behind). Pulse several times. The dough should look shaggy and hold together when pinched. If it's still too dry, add more ice water 1 tablespoon at a time, pulsing between additions. The dough should be moist but not wet or sticky.

Shape and chill: Turn dough out onto a clean surface. Gather into a ball, then divide in half. Flatten each half into a 1-inch thick disk. Wrap tightly in plastic wrap and refrigerate for at least 2 hours or up to 3 days. (Can be frozen for up to 3 months.)

Roll out: Remove one disk from refrigerator and let sit for 5-10 minutes to soften slightly. Place between two sheets of parchment paper dusted with gluten-free flour. Roll from the center outward into a 12-inch circle, about ⅛-inch thick. Rotate the dough frequently and add more flour to the parchment as needed to prevent sticking.

Transfer to pie plate: Peel off top parchment. Flip the dough into a 9-inch pie plate and gently press into the bottom and sides. Peel off remaining parchment. Trim edges leaving a 1-inch overhang, then fold under and crimp as desired.

Use as directed: For recipes requiring a pre-baked crust, prick the bottom with a fork, chill for 30 minutes, then line with parchment and pie weights. Bake at 375°F for 20 minutes with weights, then remove weights and bake 10-15 minutes more until golden.