Adzuki Bean, Tapioca Noodle, and Coconut Sweet Soup

In this classic cold sweet soup, maroon adzuki beans and chewy clear tapioca noodles, jokingly called worms in Vietnamese because they are slippery and sticky, swim in rich coconut milk. I usually prepare all the ingredients in advance and then bring everything together at the last minute. The beans and coconut milk base may be prepared a few days ahead and refrigerated until serving time, and the sugar syrup keeps in a jar in the refrigerator indefinitely. The noodles, however, are best if readied only a few hours ahead. Adzuki beans are sold at Asian markets and health-food stores. Once you have made this version, you may substitute other beans, such as black beans, hulled mung beans, or black-eyed peas. You may also blend the beans for a mixture of colors and flavors.