Rub the beef with the olive oil, salt and pepper all over.
9 lbs rib beef, olive oil, Salt, black pepper
Put a heavy-based roasting tray on the hob and when hot, add the beef.
Sear the beef quickly on all sides to colour and crisp the outside.
Transfer the beef immediately to the oven and leave the oven on its highest setting (about 240C/460F/Gas 8) for 20 minutes.
Reduce the heat to 190C/375F/Gas 5 and roast for half an hour per kilo for rare, adding another ten minutes per kilo for medium rare, 20 minutes per kilo for medium, and 30 minutes per kilo for well done.
Remove the beef from the oven, transfer it to a carving board and cover with foil. Allow it to rest in a warm place for 30 minutes.