Soak the red beans for at least 8 hours. Place the beans in a pot with 3/4 cup water (about 200 grams), bring to a boil, and cook until the beans are soft. Puree the beans until smooth, and strain if needed to remove any coarse bits. Transfer the bean paste to a pan, add the golden granulated sugar, and cook over medium heat, stirring, until the paste is thick, smooth, and no longer wet. Let cool, then roll into small balls.

To shape the dumplings: Divide the dough into equal portions. Flatten each piece, place a red bean ball in the center, and wrap the dough around it, rolling into a smooth ball. Make sure the filling is completely enclosed.

To cook the dumplings: Bring a pot of water to a boil. Gently drop the dumplings into the boiling water. When they float to the surface, transfer them to a bowl of cold water.