Instructions

1. Mix flours and salt together in a large bowl. Add butter and toss with your fingers until butter cubes are completely coated with flour. Working with your hands, gently rub about a third to a half of the butter cubes into the flour until mixture is the consistency of coarse meal flecked with cubes of butter. Sprinkle in up to 2⁄3 cup ice water, mixing dough with your hand until it just begins to hold together when pressed between thumb and forefinger; add up to 1 tbsp. more ice water, 1 tsp. at a time, if necessary. Using you hands, firmly press dough into a rough ball and transfer to a lightly floured surface. Shape dough into a 5" × 7" rectangle, straightening edges and squaring off corners with the flat side of a dough scraper. Dab any patches of sticky butter with a little flour. Wrap dough in plastic wrap and refrigerate for 30 minutes.
2. Position dough on a lightly floured surface with short edges of rectangle parallel to edge of work surface. Gently press a lightly floured rolling pin across surface of dough at 1" intervals crosswise, then lengthwise, to flatten rectangle slightly. Roll dough out into a 1⁄2"-thick rectangle about 6" wide by 13" long, straightening edges with dough scraper. Fold over short edges with dough so they almost meet in center of rectangle, and brush off any excess flour with a pastry brush. Rotate dough clockwise until long edges are perpendicular to you, then fold dough in half as if you were closing a book.
3. Repeat step 2 in its entirety, wrap dough in plastic wrap, and refrigerate for 30 minutes.
4. Repeat rolling and folding process 2 more times for a total of 4 four-fold, or book, turns. Dough should be smooth and pliable. Wrap dough in plastic wrap and refrigerate for at least 30 minutes and up to 24 hours.