1. Heat the butter in a saute pan.
2. Season the steaks, place into the pan and fry to the required degree and to a golden brown on both sides.
3. Arrange the steaks on a dish.
4. Drain the fat from the pan, add the wine and reduce by half.
5. Add the sauce, simmer and season to taste.
6. Lightly poach the marrow in a little stock and place two pieces on each steak.
7. Coat with the sauce, sprinkle with chopped parsley and serve.