In the base of a food processor combine flours, salt, and sugar. Pulse to combine.
Add the butter and pulse just until most of the butter has coated the flour (it will look slightly darker and crumbly) and the remaining pieces are no larger than peas. When I am mixing a dough with the food processor, I stop the cut in process a little sooner because I am going to continue to pulse while adding the water.
Slowly pour the water in through the feeder tube while pulsing, 1-2 tablespoons at a time. Check after about ¼ c by squeezing the dough and seeing if it holds together completely. It will most likely take about ½ cup but it is best to check as you go.
Don’t let the dough come together in the food processor. It will still look crumbly but will feel moist and hold together when squeezed.
Dump the dough out on the counter and work the dough together by gathering it and pressing away from you with the heel of your hand. Do this JUST until it comes together. If it is crumbling, then dip your hand in a little ice water and pat it on the pastry dough. Seriously, that’s it. Remember the gluten!
Press dough into a disk. Wrap in plastic wrap and chill for 2 hours or overnight. If you chill your dough overnight, you will need to let it rest a bit before rolling or it will be too cold and it will crack. It can also be frozen for up to 3 months!