Instructions

1. Preheat your oven to 400°F (200°C).
2. Remove the porterhouse steak from the refrigerator and let it rest at room temperature for about 30 minutes to ensure even cooking.
3. Generously season both sides of the steak with kosher salt and ground black pepper.
4. In a large, oven-safe skillet (preferably cast iron), heat the olive oil over high heat until it shimmers but does not smoke.
5. Carefully place the steak in the skillet and sear for 2-3 minutes without moving it, allowing for a beautiful crust to form. Flip the steak and sear the other side for another 2-3 minutes.
6. Once both sides are nicely browned, add the crushed garlic, rosemary sprigs, and unsalted butter to the skillet. As the butter melts, use a spoon to baste the steak with the butter and herb mixture for about 1-2 minutes.
7. Transfer the skillet to the preheated oven and roast for 8-10 minutes for medium-rare, or until the internal temperature reaches 130-135°F (54-57°C). Adjust cooking time for your preferred doneness.
8. Remove the skillet from the oven and carefully transfer the steak to a cutting board. Let it rest for 5-10 minutes, which allows the juices to redistribute for a more flavorful bite.
9. Slice the steak against the grain and serve with the buttery garlic-rosemary sauce drizzled over the top.