This dough may be frozen up to 1 month; thaw overnight in the refrigerator before using. Martha made this recipe on episode 509 of Martha Bakes.
Pulse flour and salt in a food processor to combine. Add butter, and pulse until mixture resembles coarse crumbs with some larger pieces remaining. Evenly drizzle 1/4 cup ice water over mixture. Pulse until dough is crumbly but holds together when squeezed. If dough is too dry, add up to 1/4 cup more water, 1 tablespoon at a time, and pulse to combine.
Turn out dough onto a floured surface, divide in half, then shape into disks. Wrap each half in plastic and refrigerate until firm, about 1 hour or up to 1 day.