Make the sauce by simmering the port and redcurrant jelly together for about 5 minutes. Sieve and keep warm.
If the steaks are thick, place each steak between sheets of cling film and flatten to about 1⁄2" thick with a rolling pin.
Put a knob of butter and the olive oil in heavy frying pan. Heat until the butter has melted.
Season the steaks, place in the pan and cook quickly on each side.
Cook according to taste.