Select a good-quality ribeye steak, about 1.25 inches in thickness and about 12 oz. It should have good marbling and a large spinalis (the rib cap) portion. The spinalis is the muscle that goes around the outside, separated from the “eye” by a layer of fat. (ALDI sells a good quality vacuum packed Choice ribeye.)
Liberally season steak with salt and pepper. Allow to come to room temperature (about 1 hour).
Preheat oven to 300 degrees. Place the steak on a wire rack over a baking sheet and roast until the internal temperature approaches 110 degrees using an instant-read digital thermometer (Thermapen sells a good quality pocket thermometer for under $20.)
Remove steak from oven and allow to rest while bringing a cast-iron skillet up to medium-high heat. When skillet is ready, sear steak on either side for no more than 45 seconds. Remove from heat and allow steak to rest again before serving.
The steak is even better if cooked on a Weber kettle grill. Prepare grill for two-zone cooking (charcoal baskets make this easy.) Add a chunk of apple, cherry, pecan or hickory to the charcoal for the roasting portion to get a good smoke flavor. Use the cast-iron directly over the charcoal for searing.