Remove the steak from the refrigerator and let it stand at room temperature for 30 to 40 minutes.

Pat the steak completely dry with paper towels to remove any surface moisture.

Season both sides of the steak with kosher salt and fresh cracked black pepper, pressing gently to adhere, and let rest for 30 minutes.

Heat a 12-inch cast iron or heavy stainless steel skillet over medium-high heat for 3 to 4 minutes until it just begins to smoke.

Add 1 tablespoon of butter to the hot pan and, once it foams and turns golden, place the steak in the pan and sear without moving for 3.5 to 4 minutes.

Flip the steak and sear the second side for 3 to 4 minutes, then add the remaining butter, smashed garlic, and thyme to the pan and tilt to baste the steak.

Continuously baste the top of the steak with the foaming butter, garlic, and thyme for about 2 minutes.

Transfer the skillet to a preheated 400°F oven and cook for 8 to 12 minutes, or until the internal temperature reaches 125°F for rare, 135°F for medium-rare, or 145°F for medium.

Remove the steak from the oven, transfer to a cutting board, tent loosely with foil, and rest for 8 to 10 minutes.

Place the skillet with pan drippings over medium-high heat, add minced shallot, and sauté for 1 minute until fragrant.

Deglaze the pan with red wine, scraping up any browned bits, and simmer for 2 minutes.

Add beef stock and simmer for an additional 2 to 3 minutes until the sauce thickens slightly.

Whisk in a small knob of cold butter and Dijon mustard, taste and adjust seasoning, then spoon the sauce over the sliced steak before serving.