Melt a knob of the butter in a frying pan over a medium high heat. Season the steaks with salt and black pepper. Add the steaks to the pan and fry for about 3 minutes on each side, Remove from the pan, cover and leave to rest for 10-12 minutes while you make the sauce.
Add the remaining butter to the same pan with the venison juices, then add the prunes and fry, stirring, for a couple of minutes. Add the wine and bring to the boil, then immediately reduce the heat to a gentle simmer.
Add the flour while stirring to thicken the sauce. Cook for about 7-8 minutes until the sauce has reduced. Season the sauce with salt and white pepper. Pour over the Venison and serve as suggested according to the season.