Toss potatoes with 1 tablespoon oil and a ¼ teaspoon each salt and pepper in a large bowl. Spread evenly on a rimmed baking sheet. Roast for 15 minutes.
Toss asparagus, tomato, and red onion with the remaining 1 tablespoon oil and a ¼ teaspoon each salt and pepper in the bowl. Stir into the potatoes on the baking sheet.
Sprinkle steak with garlic powder, rosemary and the remaining ¼ teaspoon each salt and pepper. Place on top of the vegetables. Roast until the steak is cooked and the vegetables are tender, 10 to 15 minutes.