Remove the white tendons etc. from the pork fillet and cut into approx. 2.5 cm thick slices. Heat the oil in a pan and fry the medallions for almost 2 minutes on each side, then keep warm (e.g. in the oven at 100 °).
Peel off the roasting set with the cold water and stir in the gravy. Bring to the boil briefly over moderate heat. Now stir in the crème fraîche and port wine, leave to stand for another 1 minute and add the medallions that have been kept warm.
This goes well with pasta or spaetzle and a fresh salad.