Preheat your oven to 400°F and line a small baking sheet with parchment paper.
Toss the asparagus spears and cherry tomatoes with the avocado oil and a pinch of the sea salt and black pepper on the prepared sheet.
Roast the vegetables for 12-15 minutes until the asparagus is tender and the tomatoes have just begun to burst.
While the vegetables roast, pat the sirloin steak completely dry with paper towels and season both sides with the remaining sea salt and black pepper.
Heat a cast-iron skillet over medium-high heat until it is very hot and slightly smoking.
Place the steak in the hot skillet and sear for 3-4 minutes per side for medium-rare, or until it reaches your preferred level of doneness.
During the final 2 minutes of searing, add the ghee, smashed garlic clove, and rosemary sprig to the pan.
Tilt the skillet slightly and use a large spoon to continuously baste the steak with the melted garlic-herb ghee.
Remove the steak from the pan and let it rest on a cutting board for at least 5 minutes to allow the juices to redistribute.
Slice the steak against the grain and serve alongside the roasted asparagus and blistered tomatoes.