In a small pot, slightly heat the water and dissolve brown sugar over slowest fire (to avoid too much water lost). Make sure the sugar is dissolved. Heat the liquid to a boiling and then use slowest fire. Now, add 1/2 of the tapioca starch in and mix quickly (Count 6 to 7seconds). Turn off the fire or remove from fire and add the remaining 1/2 of the tapioca starch. Mix until gathered. Quick during the process.
Place the remaining flour on an operation board. Transfer the smooth paste in and knead into a dough with the help of a scraper blade. At first, it might be slightly sticky. Continue kneading until smooth. Be quick during the process. The dough becomes hard to control when cool down completely.
Divide the dough into 4 portions. Remember to cover the other three with plastic bag. Then shape one portion into a long log (around 1.5 cm in diameter), cut the log into small cubes.
Round each small squares to small balls (be patient and do not require prefect roundness).
In a large plate, spread some flour and coat each ball with enough flour to avoid sticking to each other. After finish all of the pearls, shift the extra flour off. You can now package in air-tight bags and freeze for later use.
For the syrup: In a small pot, melt 2 slices of brown sugar slab and 1cup brown sugar with 100ml water in a small pot. Heat until there are large bubbles. Or you can simply use brown sugar syrup.
Bring a large pot of water (at least 6 times of the volume of the pearls) and cook the pears for 20 to 30 minutes. Then transfer the balls into a cold water (they shrink to original size immediately). Wash under running water. Drain and mix with 2 tablespoons of brown sugar syrup or honey (or sugar) to avoid sticky together.
For the taro ball: steam the sweet potatoes until soft. Once it is cooked and warm, mash it and mix with sugar. Mix with tapioca flour (little by little)
Transfer it to the floured surface and knead until it forms to a non-sticky dough.
Take a portion of dough, roll it out into a log about 2-cm in diameter. Cut them into pieces, dust the cut pieces generously with tapioca flour (so they wont stick to one another).
To cook taro balls, bring a pot of water to boil, add taro balls and keep stirring (so that they wont stick). Continue boiling for another 2-3 min after taro balls float on the surface. Transfer drained taro balls to a bowl of ice water to cool down (this way theyll be chewier
To serve: arrange boba pearls, taro balls, jelly (cook as per instruction) and ice cream . You can add grassjelly, sweetened red bean, milk, drizzle with honey etc.
