Want an aged steak, 1½ to 2 inches, room temperature.
Salt it aggressively on both sides. With a steak this thick, a little salt sprinkled on the outside won’t do it—make it rain.
Place the bone back in the hot pan, and reassemble the sliced meat alongside it, crust side up. Top the steak with a few fat pats of butter and duck fat.
Heat broiler and place the pan underneath. Broil till sizzling and gorgeous and a perfect medium-rare, 4–6 minutes. (Since the steak is already sliced, you can peek to check doneness.)