In the bowl of a food processor fitted with a steel blade, pulse together flours, sugar, and salt. Add butter and pulse two or three times. Add most of the water and pulse two or three times, or until butter is in pea-sized pieces. Grab a handful of the dough; if it sticks together, turn the dough out onto a lightly floured work surface. If it doesn’t stick together, add a bit more water, pulse two or three times, and test it again.
Grab the dough with both hands and push it into a ball (it may not hold very well). Using the heel of your hand, smear butter into streaks by pushing butter pieces away from you. Do this for a minute or so until the dough is mostly cohesive; it may still be a little crumbly. Divide the dough into two balls and wrap them in plastic. Refrigerate 30 minutes before baking (or you may freeze them up to three months).