1. Put milk, sugar, yeast into a mixer bowl, mix a little bit and wait for 5 minutes.
2. In the meanwhile, add salt and all purpose flour in a bowl and mix it well.
6. Whisk and mix it very well.
7. Then, turn on the fire small to medium and keep stirring it.
8. Until it thickens and let it cool down a little bit.
9. At the same time, cut 12 pieces of parchment paper into square or rectangle shape.
10. Divide custard filling into 12 pieces, roll it like a ball.
11. After the dough rises it doubles.
12. Divide the dough into 12 pieces and roll it like a ball.
13. Roll the bread dough and flatten it by using a rolling pin.
14. Place the filling in the middle of the flattened bread dough.
15. Close it and roll it like a ball. After that, place the buns on the parchment papers. Cover with a damp cloth. Let it rise for 15-20 minutes.
16. After that, place the buns into a bamboo steamer.
17. Steam it for 15 minutes.