Add the yuanxiao to a pot of boiling water, give them a gentle stir for about 10 seconds to prevent sticking, then cover the pot and bring the water back to a boil. Reduce the heat to low and add a little cold water three times to help them cook evenly. Once the yuanxiao rise to the surface, they're almost done. Cook them for another 3-5 minutes, and they'll be ready to serve.