01 - In a large bowl, combine flour, sugar, salt, and yeast, ensuring yeast does not directly contact salt. Pour in lukewarm milk, melted butter, and egg. Mix thoroughly until a sticky, cohesive dough forms.
02 - Knead the dough for 7–10 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 rectangle. 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.
05 - Fold the unbuttered third over the butter, then fold remaining third over to create a neat rectangle. Rotate dough 90 degrees so open edges face you.
06 - Roll into a 12 x 16-inch rectangle again. Perform another letter fold (folding into thirds). Wrap and refrigerate for 30 minutes.
07 - Repeat the rolling, folding, and chilling process two additional times, achieving a total of three complete turns for proper layer development.
08 - After final chill, roll dough to approximately 8 x 16 inches. Roll tightly from the short end into a loaf shape.
09 - Place seam-side down in a greased 9 x 5-inch loaf pan. Cover loosely and let rise until doubled, about 1 hour.
10 - Preheat oven to 375°F. Whisk egg with milk for egg wash and brush evenly over loaf surface.
11 - Bake for 35–40 minutes until deeply golden and hollow-sounding when tapped. Tent with foil if browning too rapidly.
12 - Let rest in pan for 10 minutes, then transfer to wire rack. Cool completely before slicing to preserve texture.