In a stand mixer fitted with paddle, mix dry ingredients and add butter on low speed. Mix for 30 seconds, until part of butter is starting to mix into the dry ingredients.
Trickle in water evenly and quickly, mixing for 20 more seconds.
Pour loose dough out onto parchment paper and using a bowl scraper and your hands, press gently into a ~6”x9” rectangle. If the dough is very dry, sprinkle +/- 2T cold water into it so it comes together loosely.
Fold the left side over toward the middle, then the right side over that. The dough will be loose but press it together as best you can. This is the first fold.
Then roll the dough out so the open edges are on either short end, till it is about 6”x16”. Use the bowl scraper to keep all edges pushed together and squared off. Fold dough in thirds again, the ‘open’ edges of the letter facing inward. This is the second fold.
Proceed with three more folds like this, for a total of five.
After the final fold, wrap dough in plastic well and chill until firm.