Bring the beef to room temperature for an hour. Preheat the oven to 180ºC/350ºF/gas 4. Drizzle the beef with 1½ tablespoon of oil, season with salt and pepper, then rub all over. Sear the beef in a hot, oiled roasting tray. Prepare a trivet of celery, carrots, onion, garlic, bay leaves and rosemary. Add the trivet to the tray, roast for 15 minutes per 500g, basting halfway. Remove beef, cover and let it rest. Make gravy with pan juices.