Instructions

For the Tangzhong

1. Whisk the ingredients together in a small saucepan.
2. Place the saucepan over low heat.
3. Keep whisking until the ingredients form a thick paste. The consistency should be thick enough so that as you whisk the mixture, the whisk leaves lines in the mixture which remains.
4. Remove the paste to a small bowl, and set it aside to cool down.

To Make the Dough

1. Measure the flour, yeast, salt and sugar into the bowl of an electric stand mixer.
2. Mix the dry ingredients together using a dough hook.
3. Add the egg and the cooled Tangzhong.
4. Slowly add the milk until the mixture comes together into a sticky dough. 
5. Add the butter, one tablespoon at a time. Wait for each tablespoon of butter to be fully incorporated into the dough before adding the next.
6. Continue kneading the dough on medium speed for about 10-15 minutes, or until the dough passes the windowpane test. (See Kitchen Notes below). By this stage, the dough should also be coming away from the sides of the bowl.
7. Lightly oil a large, clean mixing bowl.
8. Roll the dough into a smooth ball and place it into the mixing bowl.
9. Cover the dough with a clean tea towel or bowl cover, and place it somewhere warm for about 1.5 hours, or until it has doubled in size.

Portion the Filling

1. While the dough is proofing, portion the red bean filling.
2. Ideally, the red bean paste should be cold from the fridge for easier handling.
3. Portion the red bean paste into 9 balls weighing 30 g each.
4. Roll each portion into a small ball.
5. Place the balls onto a large plate or tray, and place this in the fridge until ready to use.
6. If the red bean paste you are using is quite soft and wet, you might find it easier to portion the paste using a spoon or ice-cream scoop.

Portion the Dough

1. Gently remove the dough from the bowl. The dough will deflate as you handle it.
2. Divide the dough into 9 equal portions. Use a digital scale for even-sized buns.
3. Roll each piece of dough into a smooth ball.

Shaping the Dough

1. Line a large sheet pan with baking paper.
2. Use a small rolling pin to flatten a piece of dough, about 8-10 cm/3-4 inches in diameter.
3. Place a piece of filling inside a piece of dough.
4. Cover the filling with the dough by pulling the edges of the dough into the centre, and then pinching those edges together while shaping the dough into a smooth ball as you do so. The pinched edges form the bottom of the buns.
5. Repeat the above steps with the remaining pieces of dough and filling.
6. Place the shaped buns onto the lined sheet pan.

Proving the Shaped Dough

1. Place the pan somewhere warm, covered with a clean tea towel, for about 30 minutes, or until the buns have almost doubled in size and are touching each other in the pan.

Baking the Red Bean Buns

1. Preheat the oven to 180°C/356°F.
2. Place a metal baking tray on the middle shelf.
3. Lightly brush the buns with some egg wash.
4. Sprinkle the buns with black sesame seeds. To do this the more traditional way, dip the end of a thick wooden spoon or similar (I use a wooden pestle) into the egg wash, and then dip the implement into a small bowl of black sesame seeds. Transfer the black sesame seeds to the bun by simply stamping the implement in the centre of the bun. Repeat this process for all buns.
5. Bake the buns for about 20-25 minutes, or until they are lightly golden. Check the buns at about 10-15 minutes and, if they are browning too quickly, cover the buns with a loose sheet of foil for the remaining baking time.
6. The buns are cooked if an internal thermometer reads 85°C/185°F.
7. Leave the buns on the pan for about 5 minutes to firm up, before carefully removing the buns to a wire rack to cool completely.
8. Serve warm or at room temperature.