Lupini beans must be soaked in salted water and slowly cooked in order to make them palatable by removing their toxic, bitter alkaloids.
Soak dried lupine beans overnight in salted water. Drain off the salted water, rinse them, and add them to boiling water. Reduce heat to a simmer and cook for about three hours, until the skins are smooth. They should be tender, but still firm. Soak the cooked beans in salted water (changing the water once per day) until they no longer taste bitter.