2. Cook until the mung bean blooms and the bean skin floats. Remove the bean skin for later use.

3. Boil mung beans as much as possible, then turn off the fire, remove the bean paste (mung bean soup for use) with a colander, and put it into a blender to make bean paste.

4. Put the bean paste back into the mung bean soup and cook it for a while. Add rock sugar and cook it into a uniform paste.

5. After cooling, put it in the refrigerator for cold storage. You can put some sweet-scented osmanthus or honey to taste when eating.

6. Remove the mung bean skin and mix it with brown sugar.