In a small bowl, combine the softened unsalted butter with the minced black garlic and smoked sea salt. Mix well until fully incorporated. Set aside.

Pat the ribeye steaks dry with paper towels. Rub the olive oil all over the steaks, then season generously with salt and freshly ground black pepper. Press the finely chopped rosemary into both sides of the steaks to adhere.

Preheat a cast-iron skillet or heavy-duty pan over medium-high heat until it’s very hot. Place the ribeye steaks in the skillet and sear for about 4-5 minutes on one side without moving them. Flip the steaks and cook for another 4-5 minutes for medium-rare, or until they reach your desired doneness (internal temperature of 130°F for medium-rare).

Remove the steaks from the skillet and transfer them to a cutting board. Tent loosely with foil and let them rest for 5-10 minutes. This allows the juices to redistribute throughout the meat.

Slice the ribeye steaks against the grain and serve with a dollop of the black garlic smoked sea salt butter on top. Garnish with fresh rosemary sprigs if desired.