Soft red beans are simmered into a sweet, comforting dessert soup. This traditional family treat is a beloved Chinese sweet enjoyed warm in winter or cold in summer.
Rinse the dried adzuki beans thoroughly under cold water, then soak them in fresh water for at least 3 hours or overnight to soften.
Drain the soaked beans and add them to a large saucepan with 7 cups of fresh water. Bring to a rolling boil over medium-high heat, then reduce heat to low and simmer uncovered for 60 minutes.
After 1 hour, check the beans for tenderness. If they are nearly soft, use a spoon to skim off any foam and loose skins floating on top for a smoother texture.
Add the rock sugar and salt, stirring gently. Continue simmering over low heat for another 30–45 minutes, allowing the sugar to fully dissolve and the soup to thicken. Stir occasionally to prevent scorching.
For a smoother consistency, use a ladle or potato masher to gently smash some of the beans in the pot, then simmer for an additional 10 minutes. Serve the soup warm in winter or chilled with ice for summer.