Known throughout the world by various names,
"green azuki, green gram, mung bean or mung", green soy is widespread from South East Asia to Latin America. Very nutritious, they have a delicate flavour with a hint of hazelnut, and their soft texture is perfect in soups.
In Indian cooking, hulled and split, they become moong dal: small yellow grains that cook quickly, even without soaking, and melt into a fragrant, spiced cream. And it is mung beans, sprouted, that give us the crunchy "bean sprouts" found in stir-fries and spring rolls.
Whole beans should be soaked for a few hours; to sprout them, keep them moist in a jar covered with cheesecloth, rinsing them twice a day.