Tri-colour chewy taro balls made from yellow sweet potato, purple sweet potato and taro — extra springy after an ice bath.
Peel the purple sweet potato, yellow sweet potato and taro. Cut into small chunks and steam until tender.
Mash each one separately into a fine purée while still hot.
Stir the sugar and tapioca starch into each portion while it is still warm, until crumbly.
Add hot water if the dough is too dry, more tapioca starch if too sticky. Knead until smooth and no longer sticks to your hands.
Roll each dough into a long log, cut into small pieces, and dust with tapioca starch to keep them from sticking.
Drop the taro balls into rapidly boiling water and stir gently so they do not stick to the bottom.
Boil until they all float, then 2–3 minutes more before lifting them out.
Plunge into cold water, drain, and serve.