Steps

1. Make the Tangzhong:

   • In a small saucepan, whisk flour, water, and milk until smooth.

   • Cook over medium heat, whisking, until it thickens to a paste (~65 °C / 150 °F).

   • Remove from heat, let cool to room temperature.

2. Mix the Dough:

   • In a mixing bowl (or stand mixer), combine flour, sugar, salt, and yeast.

   • Add milk, egg, and tangzhong. Mix until shaggy dough forms.

   • Knead 8–10 minutes (stand mixer) or 15 minutes by hand until smooth and elastic.

3. Add Butter:

   • Gradually knead in softened butter. Dough will be sticky at first but becomes smooth and stretchy.

   • Knead until you can stretch it into a thin windowpane without tearing.

4. First Rise:

   • Place dough in a greased bowl, cover, and let rise until doubled (~60–90 minutes, warm place).

5. Shape:

   • Punch down, divide dough into 3 or 4 equal pieces.

   • Roll each piece into a rectangle, fold sides in, then roll into a log.

   • Place logs side by side in a greased loaf pan.

6. Second Rise:

   • Cover and let rise until dough domes about 1 inch above the pan (~45–60 minutes).

7. Bake:

   • Brush with egg wash.

   • Bake at 350 °F (175 °C) for 30–35 minutes, until golden brown and internal temp reaches ~190 °F (88 °C).

   • If browning too fast, tent with foil.

8. Cool:

   • Remove from pan, cool on wire rack before slicing.