Mix Dry Ingredients
In a large bowl, whisk together the flour, salt, and sugar (if using).
Cut in Butter
Add the cold cubed butter. Use a pastry cutter or your fingers to work the butter into the flour until the mixture resembles coarse crumbs with pea-sized pieces of butter.
Add Ice Water
Sprinkle in ice water 1 tablespoon at a time, gently mixing with a fork after each addition. Stop adding water when the dough just holds together when pressed.
Form the Dough
Turn the dough out onto a floured surface. Gently press it together, then divide into two equal portions. Shape each into a disk.
Chill
Wrap each disk in plastic wrap and refrigerate for at least 1 hour (or up to 2 days).
Roll Out
When ready to use, roll one disk on a lightly floured surface into a 12-inch circle. Transfer to your pie dish, trim excess, and proceed with your pie recipe.