Remove the steaks from the fridge and let them stand on the counter until they reach room temperature, about 30 minutes. Preheat the oven to 250ºF. Place a wire cooling rack over a baking sheet. Mist the rack with cooking spray.
Pat the steaks dry thoroughly with paper towels. Season generously all over with salt; sprinkle lightly with pepper. Place on the rack and bake until an instant-read thermometer stuck into the thickest part reads 120ºF (for medium rare), 20 to 25 minutes. Remove from the oven.
Place a cast iron or other heavy bottomed skillet over medium heat until very hot, 3 to 4 minutes. Swirl the cooking fat over the bottom of the skillet and add the steaks immediately. Cook, flipping with tongs once or twice, until well seared on both sides, 2 to 3 minutes.
Transfer the steak to a cutting board, tent with foil and let rest for 5 minutes. Slice the steak against the grain and serve, sprinkling with flaky sea salt, if desired.