do in advance: slice an apple or 2, fry in butter for 5 minutes, sprinkle with cinnamon. bring punnet of blackcurrants to the boil with tiny bit of water and sugar to taste. trim the fillet
45 mins before eating: fry the fillet in a baking tray till nicely browned, put in hottish oven to roast - needs about 30 mins depending on size.
take port out of oven, leave to rest, put tin on hob, stir apple and blackcurrant into the tin, mix with all the pork juices.
I like it with green beans and roast pots or new pots