Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Cut the red potato and carrots into 1/2-inch cubes and halve the Brussels sprouts so they roast evenly.
Slice the beef sirloin tips into 1-inch bite-sized pieces, trimming any excess fat.
In a large mixing bowl, combine the beef, potatoes, carrots, and Brussels sprouts.
Drizzle with olive oil and sprinkle with sea salt, black pepper, dried rosemary, and garlic powder.
Toss everything thoroughly until the beef and vegetables are well-coated in the oil and spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the pieces are not overcrowded.
Roast for 20-25 minutes, tossing the ingredients halfway through, until the beef reaches your desired doneness and the vegetables are tender and slightly caramelized.
Remove from the oven and let rest for 2 minutes before serving warm.