Finely pulsing the butter helps create smaller air pockets in the crust, giving decorative embellishments more definition.
Process flour, salt, and sugar in a food processor until combined. Sprinkle butter evenly over top. Pulse until mixture resembles fine meal. Drizzle 5 tablespoons water over mixture. Pulse several times to combine. Add more water, 1 tablespoon at a time, and pulse until mixture holds together when pinched.
Shape dough into two disks, and wrap each in plastic. Refrigerate at least 1 hour and up to 1 day, or freeze up to 3 months (thaw overnight in refrigerator before using).