Mix glutinous rice flour and tapioca starch according to your preferred texture—use more glutinous rice flour for a softer, chewier texture, or more tapioca starch for a bouncier bite. I use a 5:1 ratio of glutinous rice flour to tapioca starch. Steam the sweet potato until soft, then mash a small piece finely (the sweet potato helps keep the dumplings soft, even after the syrup cools).

Combine the tapioca starch and glutinous rice flour, reserving a little for dusting and to adjust if you add too much water. Divide the flour into portions: 1/2, 1/4, and 1/4. Pour hot water into the largest portion (1/2), adding it gradually while stirring. Add the mashed sweet potato as you go. When the dough becomes thick and slightly lumpy, stop adding water. Add another 1/4 of the flour and mix well, then let the dough rest for 30 minutes. After resting, add the remaining 1/4 of the flour and knead until you have a smooth, uniform dough.

While the dough is resting, prepare the filling. Place the cooked mung beans in a pan with a little water or coconut milk, shredded coconut, and sugar. Stir and mash the mung beans until smooth and the sugar is absorbed. Cook until the mixture is dry enough to form into balls.

Divide the filling into small balls about 3/4 inch (2 cm) in diameter, or adjust the size as you like. Balance the amount of filling and dough so you have enough for each dumpling. If you have extra dough, you can make plain dumplings without filling. Wrap the dough around the filling, roll into balls, and dust with flour if you’re not cooking them right away. (You can prepare extra, dust with flour, and freeze them for later.)

Prepare two pots: one with boiling water and another bowl with ice water. Drop the dumplings into the boiling water; when they float, transfer them to the ice water. In a separate pot, make a ginger syrup by simmering palm sugar (or cane sugar) and ginger to taste. Once the syrup is boiling, return the dumplings to the syrup and cook for another 1–2 minutes, until they float again. Serve hot, topped with toasted sesame seeds, roasted peanuts, and shredded coconut, or simply with the warm ginger syrup. (You can substitute the mung bean filling with sesame filling by toasting sesame seeds instead of cooking mung beans; keep the other ingredients the same.)