Bring the beans to a boil and then reduce to a simmer for 1 1/2 hours. Mash until the consistency of refried beans.
Pull out the ice cream and add the bean paste. Use a mixer and blend until smooth.
Place back into the freezer. Re-mix after one hour so that the beans are even distributed throughout the ice cream.
Its consistency is like a dry gelato, mild, not too sweet. Very うま味.