Use a pepper grinder set on a coarse setting to grind the peppercorns onto a small plate. Press the steaks into the crushed peppercorns, turning until well coated. Now season with salt, if desired; adding salt before this stage draws moisture to the surface of the meat preventing the pepper from sticking properly. Heat a large frying pan until happy. Add the oil and heat, then add the steaks - you may need to do this in two batches if your pan isn’t very large. Sear until you’ve got a good crust, and don’t move them about. If you fiddle with the steaks while they’re cooking, then the crust may fall off and stick to the pan. When a good colour has been achieved on the base, turn the steaks over and leave once more to caramelise. Reduce the heat slightly, add the butter and allow it to colour a nut brown. Butter can’t stand high temperatures for long, so make sure it doesn’t burn. Add the mushrooms and work around in the butter. Your steaks won’t take long to cook be careful not to dry them out. Try to make sure the whole surface has plenty of colour and the edges of the meat are well sealed. Transfer the steaks to a baking tray and leave in a warm place to relax. This is a vital process, as when the meat cooks, the fibres shrink and force all the juices to the centre. Leaving the meat to relax will allow the juices to re-distribute, making the meat tender and succulent. Add the whisky to the pan used to cook the steaks, and heat over a very high heat for 1 minute to boil off the alcohol. A word of warning: the whisky is likely to burst into flames, so if this worries you, have a large lid handy to whack on the pan. Add the stock and reduce until thick, then pour in the cream. Reduce again, and deglaze the pan, using a heat-proof spatula to scrape and stir together any caramelised pieces stuck to the bottom. When the sauce is thick and well reduced, pour in any juices from the resting meat and stir. To serve place the rested steaks onto four warm plates and spoon over the sauce. Serve with crushed or baked potatoes and green beans.