Combine the liquid butter, marsala and pepper, brush the meat with the mixture, cover and leave to marinate in the fridge for approx. 2 hrs.
Preheat the oven to 80°C, warm the platter and plates. Heat the liquid butter in a frying pan. Brown the meat on all sides for approx. 6 mins. Remove the meat from the pan and place on a pre-warmed platter, season. Insert a meat thermometer into one of the steaks.
Cook in the centre of a preheated oven for approx. 45 mins. The core temperature should be approx. 55°C.
Beat the butter for approx. 5 mins. using the whisk on a hand mixer. Finely chop the olives, stir in and season. Refrigerate the olive butter until ready to serve.
Cut the steaks diagonally across the grain into slices approx. 3 cm thick, serve with the olive butter.
Serving suggestion: Polenta and salad.