Place roast, bone-side down, onto a rack set in a roasting pan.
Whisk olive oil, steak seasoning, garlic, Italian seasoning, and mustard powder together in a small bowl.
Spread over roast; set aside until roast comes to room temperature, about 45 minutes. Preheat the oven to 230C.
Bake in the preheated oven for 20 minutes. Insert a meat thermometer into the thickest part of the roast, not touching the bone. Reduce the oven temperature to 165C.
Continue cooking until reaches desired degree of doneness, or an internal temperature of 65C for medium is reached, about 1 1/2 to 2 hours. Remove from the oven, cover with a doubled sheet of aluminium foil, and set aside to rest in a warm area before slicing, 10 to 15 minutes.
