Remove the steak from the refrigerator 20 minutes before cooking to reach room temperature, then pat dry with paper towels.
Preheat your oven to 400°F and toss the asparagus with olive oil and half of the salt and pepper on a baking sheet.
Roast the asparagus for 10-12 minutes until tender and slightly charred.
Season both sides of the steak with the remaining salt and pepper.
Heat a heavy cast-iron skillet over medium-high heat until very hot, then sear the steak for 3-4 minutes on the first side.
Flip the steak and immediately add the ghee, smashed garlic cloves, and rosemary sprig to the pan.
Tilt the pan slightly and use a spoon to continuously baste the steak with the melting garlic ghee for another 3-4 minutes.
Remove the steak from the pan and let it rest for 5 minutes before slicing against the grain.
Serve the rested steak alongside the roasted asparagus, drizzling any remaining pan juices over the meat.