Tip the porcini mushrooms into a food processor and blitz to a powder. Put the beef in a roasting tin and rub all over with the porcini powder, smoked salt and plenty of freshly ground black pepper, do this at least 24 hrs before cooking. Cover loosely and place in the fridge overnight.

Remove the beef from the fridge at least 3 hrs before you want to cook it. Heat oven to 140C/120C fan/gas 2. Uncover the beef and cook for 1 hr 20 mins.

Turn the oven up to 220C/200C fan/gas 7 and cook for another 25 mins for medium rare until the fat is blistered and browned. If you have a meat thermometer, the core temperature should be 55C for rare, 65C for medium and 75C for well done (bear in mind that the beef will keep cooking and the temperature will continue to rise slightly as it sits). Leave to rest under a piece of foil for at least 20 mins and serve with our bone marrow stuffing, sautéed wild mushrooms and umami gravy.