Mix the marjoram, salt, and pepper, and roll the pork fillet in the mixture.

Melt the butter in a skillet and sear the pork fillet until it is golden brown on all sides.
Reduce the heat and cover.
Cook for 12 to 18 minutes, depending on the thickness of the fillet, turning occasionally, or until the pork is slightly pink in the center.

Meanwhile, in a small saucepan, simmer the prunes, balsamic vinegar, and brandy until the prunes are tender, about 15 minutes. Set aside.

Remove the pork fillet from the skillet and keep warm.
Add the prune cooking liquid and broth to the skillet, and scrape up the browned bits from the bottom of the skillet.
Increase the heat, bring to a boil, and add the currant or gooseberry jelly and heavy cream.
Simmer until the sauce thickens, about 5 minutes.

Cut the pork into 1/2-inch (1 cm) thick slices and arrange on a serving platter. Spoon the sauce over the pork and serve with green vegetables.