In a small bowl, stir together ⅓ cup (80 grams) warm water, yeast, and ½ teaspoon sugar until well combined. Let stand until foamy, 5 to 10 minutes.

In the bowl of a stand mixer fitted with the paddle attachment, beat bread flour, salt, and remaining 5 tablespoons plus 2½ teaspoons (70 grams) sugar at low speed until combined. Add 6 tablespoons (84 grams) cold butter; beat until mixture resembles coarse bread crumbs, about 2 minutes. Add remaining 1 cup (227 grams) cold butter, and pulse mixer between low speed and “off” setting just until butter is coated with flour.

Add cold milk to yeast mixture. While pulsing mixer between low speed and “off” setting, add yeast mixture to flour mixture in a slow, steady stream just until a shaggy dough comes together. (There will still be large pieces of butter.)

Turn out dough onto a surface lightly dusted with all-purpose flour, and shape into a rough 7-inch square. (Dough will be soft and slightly sticky.) Wrap in plastic wrap, and freeze for 30 minutes.

Roll dough into an 18x9-inch rectangle, lightly dusting work surface and top of dough with all-purpose flour as needed. Fold dough in half so short sides meet. Pat fold to mark center. Unfold dough, and pull one short side to center. Pull opposite side to center so short sides are touching. Pinch seams together; fold along center seam, like closing a book. Rotate dough 90 degrees; repeat rolling and folding procedure one more time. (Dough will start out soft, rough, and somewhat sticky but will come together. Turn dough over as needed so edges are rolled out as evenly as possible.) Wrap in plastic wrap, and freeze for 15 minutes.

Repeat rolling and folding procedure one more time. Wrap in plastic wrap, and refrigerate for 1 hour. (If dough is resisting or feels too soft, wrap in plastic wrap and freeze for 10 to 15 minutes before continuing.)