What kind of bean is the fennel bean in Kong Yiji's poem?

Fennel beans are a common drink in almost all hotels in Shaoxing. Soak dried broad beans (locally called Luohan beans) and drain them. Put them in a pot with Shouxiang, cork bark, salt and edible camellia. Add an appropriate amount of water and simmer over a slow fire to allow the condiment juice to be absorbed from the skin to the bean flesh. , keep the moisture and cook it until it is basically dry, remove from the pot and let it cool, and the sweet beans are ready. This kind of incense beans is green and yellow. The skin is wrinkled, the beans are tough, soft and chewy, with a refreshing and sweet flavor. Because Mr. Lu Xun wrote about fennel beans in "Kong Yiji", it became famous at home and abroad with the spread of the novel. Now, this traditional food has become a "souvenir" for tourists. After visiting the Lu Xun Memorial Hall, many foreign guests rushed to the nearby Xianheng Hotel to order a bowl of wine and a plate of mushroom beans to experience the past. Kong Yiji’s, "Life... Before leaving, I didn’t forget to take a few bags with me as gifts for my relatives and friends, and enjoy the joy of roaming around Lu Xun’s hometown.