Perfect for summer! Đậu Xanh, or 绿豆 Lu Dou, also known as mung bean in English, is an herb that is sweet and cold. It is commonly used in decocted formulas to dispel heat and toxin, and is an effective antidote for overdose of many toxic substances. It can be used topically as well! When I was little, my mom taught me how to mash up some raw mung beans to use as a paste whenever I got a cold sore.
According to Chen's Chinese Medical Herbology and Pharmacology:
Lu Dou is commonly used as a food or dessert in the summertime to clear heat, relieve thirst, alleviate restlessness, and lower body temperature. It is also effective to prevent heat stroke due to summer-heat.
Viet Nam is a hot country, and it's no wonder that a ton of our desserts use mung bean. Here's a recipe you can try that includes not only mung bean, but also two other ingredients used as herbal medicinals: lotus seed and seaweed.
1 cup mung beans, soaked in cold water overnight
1/3 cup dried lotus seeds, soaked in cold water overnight
1/4 cup dried seaweed, best with bladderwrack or kelp
1/4 cup pearl tapioca
1/3-1/2 cup sugar
1 tablespoon vanilla
7 cups water
You can find all the ingredients at any Asian food market.
Combine water and beans in a large pot and bring to a boil. Reduce heat to simmer, cook uncovered till beans are tender (about 2 hours). Add lotus seed, seaweed, tapioca, and sugar. Cook until soup thickens a little and lotus seeds are tender, but not mushy (20 minutes). Add vanilla and allow the soup cool down. If it's really hot out, you can add some shaved ice before serving. Some people like to add some coconut cream on top. Enjoy!