Make the tangzhong

• Whisk a little of the flour with some of the milk in a saucepan until smooth.
• Cook over low heat, stirring constantly, until a thick paste forms.
• Let cool slightly.

Mix the dough

• Combine the remaining flour, sugar, yeast and salt in a mixing bowl.
• Add the warm milk, the beaten egg and the cooled tangzhong.
• Mix until a shaggy dough forms.

Knead in the butter

• Knead the dough on a work surface until smooth.
• Add the softened butter gradually and keep kneading until the dough is soft, elastic and passes the windowpane test.

First rise

• Shape the dough into a ball and place it in a lightly greased bowl.
• Cover and let rise until doubled in size.

Shape the loaf

• Divide the dough into equal portions and roll each into a ball.
• Roll each ball into an oval, fold and roll up into a log.
• Place the logs side by side in the loaf pan.

Second rise

• Cover the pan and let the dough proof until it rises above the rim of the pan.

Bake

• Brush the top with a little milk or egg wash.
• Bake in a preheated oven at 180 °C until deep golden brown.
• Remove from the pan and cool on a rack.

Serve

• Slice the shokupan and spread with salted butter.