2. Wash mung beans first and soak them in boiling water for about 40 minutes;

3. Drain the water, put the mung beans into the pot, and add boiling water. The amount of water is slightly more than that of mung beans (about half an inch immersed in mung beans);

4. Cover the lid, cook over high fire, and turn off the fire when the soup will be dry;

5, add boiling water, and cover the lid tightly, stew for 20 minutes, skim off the floating skin shell, and cook for 15 minutes, the mung bean will bloom brittle, and add rock sugar to make mung bean soup.