Season the Steak: Season the steak generously with kosher salt and lightly with black pepper, ensuring to cover all sides.
Preheat the Pan: Heat a cast iron pan on medium heat with a little vegetable oil until you see wisps of smoke.
Cook the Steak: Place the steak in the pan, cooking for 3-4 minutes on one side without moving it to achieve a good sear. Flip and repeat, then sear the fatty edge. Move the steak in the fat to ensure even browning.
Add Aromatics and Butter: Add crushed garlic cloves and thyme sprigs to the pan. Lower the heat to medium, add butter, and baste the steak, focusing on any lighter spots for even browning.
Rest the Steak: Once cooked to desired doneness (140°F for medium), remove the steak and let it rest on a rack for 5-7 minutes to allow juices to redistribute.
Slice and Serve: Slice the steak against the grain if applicable, and serve with a sprinkle of coarse sea salt and thyme leaves for garnish.