Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash and peel the carrots and parsnips, then slice them into uniform 1-inch chunks to ensure they roast evenly.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, toss the chopped carrots and parsnips with half of the olive oil, half of the minced garlic, half of the herbs, and a pinch of sea salt and pepper.
Pat the chicken breast dry with a paper towel and rub it thoroughly with the remaining olive oil, garlic, rosemary, thyme, salt, and pepper.
Spread the seasoned vegetables onto the baking sheet in a single layer and place the chicken breast in the center.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep the meat succulent and flavorful.