Prepare Tang dough starter: Add bread flour and water, heat over low heat in a small pot, keep stirring until thicken like pudding, let cool and set aside.
In a small bowl, combine yeast and warm water and mix well.
Preheat the oven: “3D Hot Air” mode for 40℃
Making bread: Sieve bread flour, milk powder, salt and sugar, mix well, pour in stand mixer, or knead by hand until all ingredients are mixed well.
Add egg and water, use medium speed to knead the dough. Add dough starter and yeast mixture, mix well.
Knead the dough by stand mixer for 5 minutes. (knead for 10-12 minutes if by hands). Add the soften unsalted butter and mix well.
In a bowl, grease some oil, cover the dough with plastic wrap, put in oven to let dough fermented for 30 minutes.
Once the dough is ready, press the dough flat to release air on a lightly floured table.
Divide the dough into 8 equal parts and shape into a ball, put on a tray with baking sheet, cover with plastic wrap and allow to rise for another 30 minutes.
Preheat the oven to 180℃ by using “3D Hot Air” mode.
Prepare the Crust: Mixed all the ingredients well and make it into a dough, refrigerate for 20-30 minutes.
Divide the crust into 8 portions.
Roll the crust in between two sheets of plastic wrap, flatten the crust into circle. Place the crust on the bun.
Score the crust surface by a knife with crosshatch marks.
Brush the top of the bun with egg wash. Bake for 15 minutes at 180℃.
*Use the dough starter to make the bun more soft.