Using a food processor, combine flour and salt; then pulse once.

Add butter cut into pieces (about half the size of dice), pulse until mixture resembles coarse crumbs—larger bits may remain—around 10-12 secs. (Or do this by hand, combining dry ingredients with water & butter in large mixing bowl & a pastry blender to cut wet ingredients into dry ingredients.)

Add ice water via the tube of processor in a slow & steady stream, about half then two portions to finish just so dough begins to clump—just 30 seconds. If still too crumbly, just sprinkle a bit more, a Tblsp at a time.

Okay then—
Empty contents to very lightly floured work surface. Very gently shape dough into a ball, cut in half. Shape each half into a ball and wrap thoroughly with plastic wrap. Into the refrigerator for at least one hour, or until morning.

Option—
For what I believe is the flakiest version dough for pies, gallettes and foldovers ever (OMG); instead of using both the next day, refrigerate one ball for 1 week, then compare the difference. Note: The week old dough might turn slightly grey—don't worry—you can't tell after it's cooked, and it hasn't gone bad.

Finally—
This dough works great if you freeze it, no longer than 1 month; just move to the refrigerator the night before using.