Rinse 1 cup (200 grams) hulled split mung beans thoroughly, then soak in warm water for about 30 minutes to soften. Drain, then add the beans and 1 1/4 cups water (about 300 ml) to a pot. Cook over medium heat until the water is absorbed and the beans are soft, stirring often to prevent burning. Once the beans are tender, turn off the heat. While still hot, mash the beans with a spoon until smooth. Return the mashed beans to the stove, add a pinch of salt and 3 tablespoons sugar (adjust to taste), and stir until the sugar dissolves. Let the mixture cool slightly, then shape into small balls. Cover with plastic wrap to keep them from drying out.

In a pot, bring 4 1/4 cups water (about 1 liter) to a boil with 1/4 cup rock sugar (50 grams) and 1 tablespoon brown sugar (about 20 grams, if available). Palm sugar can be used for a richer flavor. Slice the ginger into thin strips and add to the pot. Once the syrup is boiling, gently drop in the filled rice balls. Cook until they float to the surface. Serve warm. For extra flavor, you can add coconut milk if desired.