For a small boneless sirloin roast to serve 2 or 3, purchase a 700g piece of sirloin with at least 5mm of fat attached. Ask the butcher to score the fat without penetrating the meat. Preheat the oven to 200°C, placing a small roasting tin with a rack inside the oven while it heats. Rub salt into the fat and lightly season the meat with salt and pepper. Seal the beef in very hot clarified butter or olive oil in a frying pan, beginning with the fat edge, then transfer to the roasting tin. Roast for 15 minutes, then loosely cover with foil and allow to rest for 10 minutes.