Remove the steak from the refrigerator 20 minutes before cooking to reach room temperature, then pat it completely dry with paper towels.
Season both sides of the steak generously with the sea salt and black pepper.
Heat a heavy cast-iron skillet over medium-high heat until it is just beginning to smoke.
Place the steak in the hot skillet and sear for 3-4 minutes without moving it to develop a deep, caramelized crust.
Flip the steak and immediately add the ghee, smashed garlic cloves, and rosemary sprig to the pan.
Tilt the pan slightly and use a large spoon to continuously pour the melting garlic-herb ghee over the steak for 2-3 minutes until desired doneness.
Transfer the steak to a cutting board to rest for 5 minutes; meanwhile, toss the asparagus into the same pan to sauté in the remaining juices until bright green.
Slice the steak against the grain and serve immediately alongside the tender asparagus.