Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Finely mince the garlic cloves, fresh rosemary, and fresh thyme leaves.
In a small bowl, whisk together half of the olive oil with the minced garlic, rosemary, thyme, sea salt, and black pepper.
Pat the pork tenderloin dry with a paper towel and rub the garlic-herb mixture over all sides of the meat.
Trim the ends of the Brussels sprouts and cut them in half; peel the carrots and slice them into half-inch rounds.
Place the vegetables on the prepared baking sheet, drizzle with the remaining olive oil, and toss to coat evenly.
Move the vegetables to the edges of the pan and place the seasoned pork tenderloin in the center.
Roast in the oven for 20 to 25 minutes, or until the pork reaches an internal temperature of 145°F (63°C) and the vegetables are tender.
Remove from the oven and let the pork rest on a cutting board for 5 to 10 minutes before slicing into medallions to serve.