1. Prepare the filling In a large bowl, add all the ingredient "A" and mix everything together until well combined. Now cover it and refrigerate until your dough is ready.
2. In a medium bowl, combine the dough ingredients (wheat starch, tapioca starch and salt). Slowly stir in the boiling water. Mix and knead using a spatula. Then when the dough is cool enough to handle, knead the dough for a couple of minutes with your hands until it turns into a smooth dough ball shape.
3. Roll the dough into a long cylinder, and cut it into equal pieces (each about 12~13g). Cover the dough pieces with a damp cloth or paper towel to prevent it from drying out while you make the dumplings.
4. Put it all together Take one piece of the dough and flatten it using a kitchen tool (I used a dough scraper). Then roll the dough into about 8cm diameter discs using a rolling pin. Add a spoonful of filling. Lift the edge of the wrapper and fold it over the filling. Make some pleats using your fingers and pinch the edges to close the dumpling. Continue making dumplings until you use up all the dough.
5. Now steam the dumplings for about 15 minutes, or until the wrappers turn translucent.