I remembered my late paternal grandmother often made these for the family. However, I did not manage to learn the recipe for the soon kueh skin. I only remembered that she had to steam yam and mashed it. She also took out a dough and cooked it in boiling water. I googled and found this method quite similar to my grandmother's. http://wlteef.blogspot.sg/2008/10/hakka-soon-kueh.html
I also cooked the filling based on estimation and my family's taste.
1. Steam 300g yam and mash them with 150g of tapioca flour. I omit 5 spice powder as I don't remember my grandmother using them.
2. I fried dried cuttlefish, dried shrimps, black fungus, chinese mushrooms. orange tau kwa with the turnips.
When I was wrapping the soon kueh, I was thinking it shall be my last attempt. It was so hard managing the skin. they broke easily. :(
However, I will attempt again as I was quite satisfied with the results.