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 beaten egg. Mix thoroughly until a sticky, cohesive dough forms.
02 - Knead the dough on a lightly floured surface 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 tightly and refrigerate for 30 minutes to firm the gluten structure.
04 - On a 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 rectangular package. 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 and folding process two more times, chilling for 30 minutes between each turn, for a total of three complete laminations.
08 - After the final chill, roll dough to approximately 8 x 16 inches. Starting from the short edge, roll tightly into a cylinder and pinch the seam to seal.
09 - Place the loaf seam-side down in a greased 9 x 5-inch loaf pan. Cover loosely with plastic and let rise until doubled, about 1 hour.
10 - Preheat oven to 375°F. Whisk together egg and 1 tablespoon milk for the egg wash. Brush the entire surface of the risen loaf evenly.
11 - Bake for 35–40 minutes until deep golden brown and the loaf sounds hollow when tapped on the bottom. Tent with aluminum foil if the top browns too quickly.
12 - Allow the loaf to rest in the pan for 10 minutes, then transfer to a wire rack. Cool completely before slicing to preserve the delicate interior structure.