01 - In a large bowl, combine flour, sugar, salt, and yeast, placing yeast away from direct salt contact. Pour in lukewarm milk, melted butter, and cracked egg. Mix thoroughly until a sticky, cohesive dough forms.
02 - Knead the dough vigorously for 7 to 10 minutes until smooth and elastic. Transfer to a greased bowl, cover, and let rise for 1 hour until doubled in volume.
03 - Punch down the risen dough and shape into a rectangular form. Cover and refrigerate for 30 minutes to firm.
04 - On a lightly floured surface, roll dough into a 12 x 16-inch rectangle. Arrange cold butter slices over two-thirds of the dough surface, leaving a 1-inch border.
05 - Fold the unbuttered third over the center, then fold the remaining third on top to create a neat rectangle. Rotate the dough 90 degrees so the open edges face you.
06 - Roll the dough again into a 12 x 16-inch rectangle. Perform a letter fold by folding into thirds. Wrap tightly and refrigerate for 30 minutes.
07 - Repeat the rolling, folding, and chilling process two more times for a total of three complete turns, chilling 30 minutes between each.
08 - After the final chill, roll dough to approximately 8 x 16 inches. Roll tightly from the short edge into a cylinder and place seam-side down in a greased 9 x 5-inch loaf pan.
09 - Cover loosely and let rise until doubled in size, about 1 hour. The dough should spring back slowly when touched.
10 - Preheat oven to 375°F. Whisk together egg and milk for the egg wash. Brush the entire surface of the risen loaf gently.
11 - Bake for 35 to 40 minutes until deeply golden brown and the loaf sounds hollow when tapped on the bottom. Tent with foil if the top browns too quickly.
12 - Let cool in the pan for 10 minutes, then transfer to a wire rack. Cool completely before slicing to preserve the flaky texture.