Shokupan Japanese Milk Bread Loaf

In a small saucepan, whisk together 1/4 cup bread flour, 1/2 cup water, and 1/2 cup milk until smooth. Cook over medium-low heat, stirring constantly, until the mixture thickens to a paste-like consistency, about 3-5 minutes. Remove from heat, transfer to a bowl, cover with plastic wrap directly on the surface, and let it cool completely to room temperature.

In the bowl of a stand mixer, combine the remaining 3 cups bread flour, granulated sugar, salt, and instant dry yeast. Mix briefly to distribute.

Add the cooled tangzhong, 1/2 cup lukewarm milk, and the room temperature egg to the dry ingredients. Using the dough hook attachment, mix on low speed until a shaggy dough forms. Increase speed to medium-low and knead for about 5-7 minutes until the dough comes together.

Add the softened unsalted butter, one tablespoon at a time, continuing to knead until fully incorporated. Increase speed to medium and knead for another 10-15 minutes until the dough is smooth, elastic, and passes the windowpane test (a small piece can be stretched thinly without tearing).

Form the dough into a ball and place it in a lightly oiled large bowl. Cover the bowl with plastic wrap and let it rise in a warm place for 1 to 1.5 hours, or until doubled in size.

Gently deflate the risen dough. Turn it out onto a lightly floured surface. Divide the dough into 3 equal pieces. Roll each piece into a rectangle, then fold the longer sides towards the center, overlapping slightly. Roll it up tightly from one end to the other into a log. Repeat with the remaining pieces. Place the three logs seam-side down into a greased 9x4-inch (23x10 cm) loaf pan.

Cover the loaf pan loosely with plastic wrap or a damp cloth and let it rise in a warm place for another 45-60 minutes, or until the dough has risen about 1 inch above the rim of the pan.

Preheat oven to 375F (190C). Optionally, brush the top of the risen dough with a little milk for a golden crust. Bake for 30-35 minutes, or until the top is golden brown and sounds hollow when tapped. If the top browns too quickly, tent loosely with foil.

Remove the loaf from the oven and immediately turn it out onto a wire rack to cool completely before slicing. This prevents the bottom from becoming soggy and ensures the best texture.