Preheat your oven to 425°F (220°C) for a perfect sear on the steak.
In a mixing bowl, combine baby potatoes, broccoli florets, yellow bell pepper, red onion, and minced garlic. Drizzle with olive oil and sprinkle with salt, pepper, and Italian seasoning. Toss until evenly coated.
Season the sirloin steak generously with salt and pepper on both sides. Optionally rub with olive oil for extra flavor.
Spread the seasoned vegetables on one side of the sheet pan and place the steak on the other side.
Roast in the oven for about 20-25 minutes, or until the steak reaches your desired doneness.
Remove from oven and let the steak rest for about 5 minutes before slicing. Serve alongside the roasted veggies.