Steam the purple sweet potato for 15-20 minutes until the purple sweet potatoes are tender. Check this by poking the sweet potatoes with a fork/skewer.

While the purple sweet potatoes are being cooked, prepare the palm sugar porridge by adding water, palm sugar, granulated sugar, pandan leaves, and salt into a medium pot. Bring to a boil and turn off the heat. Strain to remove pandan leaves and any residual from the palm sugar. Set aside.

In a small saucepan, add coconut milk, salt, and pandan leaves. Simmer with low heat while stirring constantly. Turn off the heat and set aside.

After the purple sweet potatoes are cooked, put them in a medium bowl and mash until smooth while still warm. Add tapioca flour and salt and knead the dough with hand until fully incorporated. Roll the dough into 1-1.5 inch balls with your hands and put them on a clean tray.

In a medium pot, add enough water to reach half of the pot. Let it boil and add sweet potato balls into the water. Cook until the sweet potato balls float to the top. Using a strainer, transfer the cooked sweet potato balls into the palm sugar water.

Bring the palm sugar water to boil. In a small bowl, mix tapioca flour and water until incorporated. Pour the mixture into the palm sugar water until the porridge thickens and starts to bubble. Remove from the heat.

To serve, ladle some sweet potato balls along with the palm sugar porridge into a serving bowl. Drizzle with a generous amount of coconut milk.