Peel and steam your taro and sweet potatoes, measure 100 grams of each steamed root vegetable;
Mash the steamed root vegetable until very smooth, add in the flour, and stir with a fork to bring them together, they'll form a gravel like mixture, then use your hand to knead the mixture until it forms a smooth, soft dough;
If the dough is too dry and cracks when you try to shape them, add the hot boiling water little by little while continue to knead, don't add it in all at once, adjust and knead until you achieve a soft dough;
Divide each dough ball into two pieces, roll each piece into a long thin strip, about 1/2 inch thick, then cut them into small bite size pieces;
Dust them with a generous pinch of tapioca flour so they won't stick to each other, keep any extra balls in the freezer;
Bring a big pot of water to boil, drop the taro balls and sweet potato balls in, wait till they all float to the surface, then cook another 2 minutes;
Remove the cooked balls and immediately drop them in the ice bath for the best chewy texture;
Serve with your preferred toppings, a drizzle of condensed coconut milk and soy milk, enjoy!