Position an oven rack in the center, heat the oven to 275°F (135ºC), and line a rimmed baking sheet with foil or parchment paper before setting a wire rack on top. The raised rack keeps the steak elevated so its underside dries along with the top and sides.

Blot the steaks thoroughly with paper towels, place them on the rack, and season both sides generously with kosher salt and black pepper. The surface should look dry rather than shiny before it goes into the oven.

Bake until the thickest center reaches 85 to 90°F (29 to 32ºC) for rare, 90 to 95°F (32 to 35ºC) for medium-rare, 100 to 105°F (38 to 41ºC) for medium, 110 to 115°F (43 to 46ºC) for medium-well, or 120 to 125°F (49 to 52ºC) for well done, checking often after 15 minutes. This stage takes about 15 to 25 minutes, depending on thickness and preferred doneness, and the exterior should look lightly dry and matte.

Heat a 12-inch cast iron skillet or stainless steel pan over high heat for a few minutes, add the vegetable oil, then sear the steaks for 1 to 2 minutes on each broad side once the oil is just beginning to smoke. The beef should make an immediate loud sizzle and develop a deep brown crust rather than a pale, damp surface.

Use tongs to hold each steak on its sides for 30 to 60 seconds per side, cooking the fat edges until softened and browned; continue until the center reaches 115 to 120°F (46 to 49ºC) for rare, 120 to 125°F (49 to 52ºC) for medium-rare, 130 to 135°F (54 to 57ºC) for medium, 145 to 150°F (63 to 66ºC) for medium-well, or 155°F (68ºC) for well done. The fat cap should look rendered and feel less firm when pressed with the tongs.

Lower the heat to medium-low, add the unsalted butter if using, and spoon the melted butter over the steaks for 1 minute before moving them to a clean plate or cutting board to rest for 5 to 10 minutes. The butter should foam gently, and the steak should remain warm and juicy when sliced.