Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
In a small bowl, mince the garlic and whisk it together with half of the olive oil, rosemary, thyme, salt, and pepper to create a thick herb paste.
Pat the beef sirloin dry with a paper towel and rub the herb paste evenly over all sides of the meat.
Place the seasoned beef in the center of the prepared baking sheet.
In a separate bowl, toss the trimmed green beans and sliced carrots with the remaining olive oil and a small pinch of salt.
Arrange the vegetables in a single layer around the beef on the baking sheet.
Roast for 20 to 25 minutes, or until the beef reaches an internal temperature of 135°F for medium-rare and the vegetables are tender-crisp.
Remove from the oven and transfer the beef to a cutting board, letting it rest for 10 minutes to lock in the juices.
Slice the beef thinly against the grain and serve alongside the roasted vegetables.