Cut the beef liver into three to four pieces. These should each be a little smaller than half a slice of ham.
First place a sage leaf on the ham, then a piece of liver and another sage leaf. Fold the ham over.
Fry both sides in the heated oil with the remaining sage leaves (for the garnish) until crispy, keep warm.
Pour the roast set with Marsala and poultry stock and dissolve, let it reduce a little. Stir in the ice-cold butter to bind, season with salt and pepper.
Pour a little pepper over the liver packets, cover each with a fried sage leaf and serve with the sauce.