Soak the white beans in cold water in the evening. After 15 hours, drain the water, and rinse the beans with running water. Pour the beans into a saucepan, fill with water so that the beans are completely in the water. Cook it on low heat until soft for about 70 minutes. Set aside some beans for the filling. Pour in the broth and bring to a boil. (During the fast, it is better to use vegetable broth.)