Bring at least 6 cups of water to boil in a pot. Add uncooked small tapioca pearls and cook until almost fully translucent (~15 mins), stirring occasionally.
While the tapioca cooks, peel and dice taro into ½ inch cubes. Some people may have a reaction to the skin of the taro while peeling, so it's best to wear gloves while preparing the taro.
Once the tapioca / sago is mostly translucent (a tiny white dot in the middle is ok), pour it into a strainer, rinse with cold water, then let sit in a bowl of water until you need it — this prevents it from hardening and sticking to each other.
Bring 4 cups of water to boil in a large pot, then add half of the cubed taro and the yellow rock sugar (or 2 tbsp white sugar). Let simmer 10-15 min, or until taro is soft.
Add coconut milk, evaporated milk, and condensed milk if using. Add remaining taro and cook for 10-15 min or until soft.
Taste and adjust sugar levels to your preference. I added another ~¾ oz (20g) of yellow rock sugar here but it’s not necessary if you prefer it less sweet.
Lastly, add the drained tapioca pearls and mix. It’s ready to serve hot, or you could let it cool and serve cold. This soup tastes even better after a few hours because the coconut milk and flavors absorb better into the taro. Enjoy!
