JW,
that's one of my fav. baos too. but its' very difficult to make it at home as you need to have the skill to make the super think skin for the bao. and you have to make the cubes of the soup that's supposed to be melted when the buns are steamed. i will see if i can find a recipe. if, not i hope someone else can help you. i just eat them in the restaurants... :( sorry can't be more helpful