Preheat your oven to 400°F. Halve the baby potatoes and toss them on a baking sheet with a light drizzle of oil, garlic powder, and a pinch of salt. Roast for 20-25 minutes until the skins are crispy and the insides are tender.
While potatoes roast, pat the sirloin steak completely dry with paper towels to ensure a perfect sear, then season both sides generously with sea salt and black pepper.
Heat a heavy cast-iron skillet over medium-high heat with the avocado oil until it begins to shimmer and just starts to smoke.
Carefully place the steak in the hot skillet. Sear undisturbed for 3-4 minutes to develop a deep, caramelized brown crust.
Flip the steak and immediately add the ghee, smashed garlic cloves, rosemary, and thyme to the pan.
Tilt the skillet slightly so the melted ghee pools with the aromatics. Use a large spoon to continuously baste the steak with the hot herb-infused fat for another 3 minutes for medium-rare.
Transfer the steak to a wooden cutting board and let it rest for at least 8 minutes to allow the juices to redistribute.
While the steak rests, toss the asparagus spears into the same hot skillet with the remaining pan drippings. Sauté for 3-4 minutes until bright green and tender-crisp.
Slice the rested steak against the grain and serve alongside the roasted potatoes and sautéed asparagus.