Steam the salted egg yolks for 10 minutes. Transfer to a bowl and mash.
Add condensed milk and butter to the egg yolks and whisk thoroughly until well combined and smooth. Mix in coconut cream and milk powder. Cover and chill until set and firm.
Scoop firm filling into even portions and freeze.
In a bowl, combine lukewarm water, yeast, and sugar. Set aside until foamy.
In another bowl, mix the dry ingredients.
Add the dry ingredients and vegetable oil into the bowl with yeast and mix. Knead with hands until dough forms. Let the dough rest in a warm place for 1 hour.
Form dough into balls and allow to rest for 30 minutes.
Flatten the siopao dough and place the salted egg custard filling in the middle. Fold the dough and seal the filling in the middle.
Place dough in sturdy cupcake liners and steam for 10 minutes.
Serve warm.
Servings 0