Preheat your oven to 425°F (220°C).
Peel (if desired) and dice the sweet potato into 1/2-inch cubes. Toss with half the olive oil, salt, and pepper.
Spread the sweet potato cubes on a baking sheet and roast in the oven for about 20-25 minutes until tender and lightly caramelized.
While the sweet potato is roasting, cut the broccoli into florets. Toss with a drizzle of olive oil, salt, pepper, and a pinch of garlic powder, then spread out on a separate baking sheet.
Roast the broccoli in the oven for about 15-20 minutes until tender with slight crispy edges.
Meanwhile, pat the sirloin steak dry with a paper towel. Season both sides with salt, pepper, and a pinch of garlic powder.
Heat a skillet or cast iron pan over high heat. Once the pan is hot, sear the steak for about 3-4 minutes on each side for medium-rare, or adjust time to your preference.
Remove the steak from the skillet and let it rest for 5 minutes before slicing against the grain.
Plate the sliced steak alongside the roasted broccoli and sweet potato, and serve immediately.