Preheat your oven to 400°F (200°C).
Dice the sweet potato into 1/2-inch cubes and toss them in a bowl with the extra virgin olive oil, dried rosemary, and half of the sea salt and black pepper.
Spread the sweet potatoes in a single layer on a parchment-lined baking sheet and roast for 15 minutes.
Toss the asparagus spears onto the same baking sheet with the sweet potatoes and roast for an additional 10 minutes until the potatoes are golden and the asparagus is tender.
While the vegetables roast, season both sides of the sirloin steak with the remaining sea salt and black pepper.
Heat a cast-iron skillet over medium-high heat. Once hot, sear the steak for 3 to 4 minutes per side for medium-rare.
Reduce the heat to medium-low and add the ghee and smashed garlic cloves to the skillet.
Tilt the pan slightly and use a spoon to continuously baste the steak with the melted garlic ghee for 1 minute.
Remove the steak from the pan and let it rest for 5 minutes before slicing against the grain.
Plate the sliced steak alongside the roasted sweet potatoes and asparagus.