Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.
Toss the cubed sweet potatoes with 1 tsp of olive oil, garlic powder, and half of the salt and pepper.
Spread sweet potatoes on the sheet and roast for 20-25 minutes until the edges are golden and caramelized.
While potatoes roast, season the steak on both sides with the remaining salt, pepper, and dried rosemary.
Heat the remaining 1 tsp of olive oil in a heavy skillet over medium-high heat until shimmering.
Place the steak in the pan and sear for 3-5 minutes per side, depending on thickness, for a perfect medium-rare.
Remove the steak from the pan and let it rest on a cutting board for 5 minutes to lock in the juices.
In a separate pot, lightly steam the green beans for 4-5 minutes until bright green and tender-crisp.
Slice the steak against the grain and serve alongside the roasted potatoes and steamed green beans.