Bring 5 cups of water to a rolling boil in a medium pot. Add the tapioca pearls, reduce heat to a simmer, and cook for about 15 minutes until translucent. Cover and let rest for 10-15 minutes, then strain and rinse under cold water.

Peel the taro root with a knife or vegetable peeler, wearing gloves. Cut taro into uneven 1-inch cubes and set aside.

Combine cubed taro, rock sugar, and enough water to cover in a large pot. Boil over medium-high heat, reduce to a simmer and cook for 20 minutes or until taro is tender.

Stir in coconut milk into the cooked taro mixture and simmer for an additional 5 minutes until the dessert thickens.

Drain previously prepared tapioca pearls and gently fold into the taro coconut mixture. Serve warm or chill overnight.