Steam or boil the sweet potato pieces for about 7 minutes until fork tender. Cool them in a colander for ten minutes so that they can be comfortably handled.

In a large mixing bowl, combine the cooled sweet potato, tapioca flour, and salt. Use your hands to knead the mixture until it forms a smooth, dough-like consistency.

Roll the dough into small balls, using about 1 heaping tablespoon for each ball.

Bring a pot of water to a rolling boil over a high flame. Add the formed sweet potato balls to the boiling water and cook for just a couple of minutes until they rise to the surface. Carefully remove them with a slotted spoon.

In a deep saucepan, bring the water, knotted pandan, palm sugar (or coconut sugar) and salt to a boil over high heat.

In a separate small bowl, mix the tapioca starch with water to create a smooth paste. Remove the pandan leaves and slowly pour the starch slurry into the simmering sugar water, stirring continuously. Once bubbling, turn off the heat, and set aside.

In another saucepan, combine the canned coconut milk, knotted pandan leaves, half a teaspoon of salt, and half a teaspoon of vanilla extract. Heat this mixture gently over low heat while stirring. Allow it to simmer for a few minutes until it's fragrant and slightly thickened. Remove the pandan and set aside.

To serve, ladle a generous amount of palm sugar porridge into each bowl, add a few sweet potato dumplings, and drizzle with the aromatic coconut sauce. Optionally garnish with grated coconut, one or two mint leaves and a thin slice of fresh pandan.