1. Rinse the beans several times and put them in a large volume of water. Bring to a boil and cook for 5 minutes. Drain the water and repeat.
2. In a pot, add the beans and 700ml of water. Cook on low heat for at least 1 hour or 1 hour and a half, until the beans are well cooked. Beans should be tender and easily crushed by a fork or a finger.
3. Drain the water and add sugar while stirring for approximately 15 minutes, to obtain a compact paste. Add more water if necessary, a pinch of salt and mix thoroughly one last time.
Et vvoilà ! Enjoy it as a filling for your dorayaki, taiyaki and mochi or simply spread it on a slice of bread.