Take the steak out of the refrigerator and let it sit at room temperature for about 30 minutes before cooking. This helps it cook evenly.
Pat the steak dry with paper towels to remove excess moisture. Season both sides generously with salt and black pepper.
Heat a large cast-iron skillet or heavy frying pan over medium-high heat. Add the olive oil and allow it to heat until shimmering but not smoking.
Carefully place the steak in the hot skillet. Sear for about 4-5 minutes without moving it, until a nice crust forms.
Flip the steak and add the smashed garlic cloves and butter to the skillet. Cook for another 4-5 minutes for medium-rare, or until your desired doneness is reached.
As the steak cooks, use a spoon to baste it with the melted butter and garlic for extra flavor.
Once cooked to your liking, remove the steak from the skillet and let it rest on a cutting board for about 5-10 minutes before slicing.
If desired, garnish with fresh rosemary or thyme before serving.