Sallad of old cabbage, roasted bone marrow and raw heart, toasts and salt

1 whole marrow bone
1 heart, room temepratured
1 head of very nice winter cabbage cleaned from the outer leafs
1 good loaf of bread, a bit acidic and not to white, preferably a couple of days old
iodine free sea salt

Place the marrow bone directly on the burning charcoal, let it cook for about five minutes.
While the bone cooks, finely dice the heart.
Open the bone and scoop out the marrow into a warm ceramic bowl, add the raw heart and cut some cabbage which should also be added.
Serve the mixture with some toats prepared on a griddle over the charcoal and a litle salt.