Runny salted egg yolk bao (Lau sa lai wong bao)

Instructions

1. Pour water into a medium saucepan to a depth of about 3 cm and bring to the boil. Arrange all the egg yolks on a steamer tray or plate, then cover and steam for 10 minutes or until fully cooked.
2. Transfer to a small bowl and mash with a fork. Mix in the powders, sugar and butter until well combined, then cover and put in the fridge for 15 minutes.
3. To make the dough, place the flour, yeast, baking powder and sugar in a large bowl and mix well. Add 125 ml (½ cup) water and stir gently with your hand until all the ingredients start to come together. Gently knead the dough in the bowl for 5 minutes, then cover with plastic wrap and leave to rest for 10 minutes.
4. Turn out the dough onto a clean bench and knead for another 10 minutes or until smooth.
5. Put the dough in a medium bowl, cover with a clean damp cloth and leave the dough to prove for 1–1½ hours or until it has nearly doubled in size.
6. Meanwhile, turn the egg filling out and portion into 12 even-sized balls. Cover with plastic wrap and return to the fridge.
7. Gently knock back the dough, then roll it into a cylinder. Cut into 12 even pieces and roll into balls. Let them rest for 5 minutes.
8. Flatten each ball of dough into an 8 cm round with thinner edges and put a portion of egg filling in the middle. Fold over to enclose, slightly pulling and turning the dough as you go. Place on a lined tray, seam side down, and rest for another 15 minutes.
9. Pour water into a large saucepan to a depth of about 3 cm and bring to the boil. Arrange the buns on a steamer tray or plate in a single layer, then cover and steam for 10 minutes. Depending on the size of your steamer you may need to do this in two batches.
10. Serve immediately, and be careful as the egg filling will be like hot running lava!