Place the steak on a dinner plate and sprinkle both sides with the Devil’s Backbone Seasoning. Set the steak aside.
Place the cast iron grill pan over the burner on your stove, and turn the heat to medium-high. Let the pan get very hot, which takes about 4 minutes. You will see the pan begin to smoke. Turn on your exhaust fan.
Brush the grill pan with the oil. Lay the steak down on the pan, and do not move it for 4 minutes. It will sear, and as the outside sears, the steak will actually release itself from the pan. With tongs, turn the steak and let it sear on the other side, about 3 to 4 minutes.
Depending on the thickness of the steak, and whether you want the steak pink in the center or cooked through, the steak may be ready or need a little more cooking. Turn off the heat under the grill pan, and let the steak remain on the grill pan until – using a digital thermometer – the steak registers – 130 to 135 for medium-rare, or 140 for medium. If the steak is thick and needs more cooking time to reach the desired degree of doneness, place the grill pan and steak in a 350-degree oven until done.
If desired, place a pat of butter on top of the steak before carving and serving.