Bring the steak to room temperature for 20 minutes and pat it completely dry with paper towels.
Season both sides of the sirloin evenly with sea salt and black pepper.
Steam or boil the sweet potato until tender, then mash until smooth and creamy.
Toss the asparagus spears with extra virgin olive oil and a pinch of salt, then roast or sauté until crisp-tender.
Heat a heavy cast-iron skillet over medium-high heat until it is very hot and slightly smoking.
Place the steak in the pan and sear for 3-4 minutes per side for a perfect medium-rare.
Reduce the heat to medium and add the ghee, smashed garlic clove, thyme, and rosemary to the skillet.
Tilt the pan slightly and use a spoon to baste the melting herb ghee over the steak for about 1 minute.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes before slicing against the grain.
Plate the sliced sirloin alongside the mashed sweet potato and roasted asparagus, drizzling any remaining pan juices over the meat.