Notes: This recipe is designed for very large bone-in steaks, at least 1 1/2 to 2 1/2 inches thick and weighing 1 1/2 to 2 pounds. Porterhouse, T-bone, rib-eye, and New York strip will all work well. Do not use tenderloin steaks, as they are likely to overcook.
For best results, let the steak rest for at least 45 minutes at room temperature or up to 3 days, uncovered, on a rack set in a rimmed baking sheet, in the refrigerator after seasoning it.
1. Carefully pat the steak dry with paper towels. Season liberally on all sides (including the edges) with salt and pepper.
2. Heat the oil in a 12-inch cast-iron skillet over high heat until just beginning to smoke. Carefully add the steak, reduce the heat to medium-high, and cook, flipping the meat frequently, until a pale golden brown crust starts to develop, about 4 minutes.
3. Add the butter and herbs and shallots, if using, to the skillet and continue to cook, flipping the steak occasionally and basting it with the foaming butter, shallots, and thyme until an instant-read thermometer inserted into thickest part of the steak, away from the bone, registers 120°F for medium-rare, or 130°F for medium, 4 to 8 minutes longer. To baste, tilt the pan slightly so that butter collects by the handle and use a spoon to pick up the butter, and pour it over the steak, aiming at the light spots. If the butter begins to smoke excessively or the steak begins to burn, reduce the heat to medium. When the steak is done, transfer it to a rack set in a rimmed baking sheet. Let rest for 5 to 10 minutes. Reheat pan drippings until smoking, and pour over steak to re-crisp.
4. Carve the steak and serve.
Excerpted from The Food Lab: Better Home Cooking Through Science by J. Kenji Lopez-Alt. Copyright © 2015 by J. Kenji Lopez-Alt. With permission of the publisher, W. W. Norton & Company, Inc. All rights reserved.