Rinse lima beans and then soak at least three hours.  Place beans and ham steak in a pot and add water until the beans are covered and the water level is an inch above the beans.  Bring to a boil and then turn down to a simmer.  Simmer until beans are super tender (about an hour to an hour and a half).  Salt and pepper to taste and stir in the butter.  Goes great with cornbread.