Cut the cabbage into quarters. Remove the cores and then slice fairly thin. Melt the butter in an ovenproof casserole dish and add the ham cut into little sticks about 1 inch long.
Let it simmer gently in the butter without browning for 5 minutes; then stir in the cabbage and turn it over in the butter until it is all coated and glistening. Cover the dish and allow it to sweat for 10 minutes. Stir in the vinegar, sugar and seasoning and cover the dish. Bake very gently at 325 degrees F for 2 hours, stirring occasionally.