Preheat your oven to 400°F and line a baking sheet with parchment paper.
Dice the sweet potato into 1/2-inch cubes and trim the woody ends off the asparagus.
Toss the sweet potato cubes with half of the avocado oil and a pinch of salt, then roast for 15 minutes.
Add the asparagus to the baking sheet, drizzle with the remaining avocado oil, and roast for an additional 10-12 minutes until tender.
Pat the sirloin steak dry with paper towels and season both sides generously with sea salt and black pepper.
Heat a cast-iron skillet over medium-high heat until very hot, then place the steak in the pan to sear for 3-4 minutes per side for medium-rare.
During the last 2 minutes of cooking, add the ghee, smashed garlic clove, and rosemary sprig to the pan.
Tilt the pan and use a spoon to continuously baste the steak with the melted garlic herb ghee.
Remove the steak from the pan and let it rest for at least 5 minutes before slicing against the grain.
Serve the sliced steak with the roasted sweet potatoes and asparagus, drizzling any remaining pan juices over the meat.