Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and slice the carrots and parsnips into 1/2-inch thick rounds.
In a bowl, toss the sliced vegetables with 0.5 tablespoon of olive oil, a pinch of sea salt, and black pepper.
Spread the vegetables in a single layer on the baking sheet.
Rub the pork tenderloin with the remaining 0.5 tablespoon of olive oil, dried rosemary, garlic powder, and the rest of the salt and pepper.
Place the pork in the center of the baking sheet, surrounding it with the vegetables.
Roast for 20 to 25 minutes, or until the pork reaches an internal temperature of 145°F (63°C).
Remove from the oven and let the pork rest for 5 to 10 minutes before slicing into medallions to ensure it remains juicy.
Serve the sliced pork with the caramelized root vegetables.