Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel the carrots and parsnips, then slice them into 1/2-inch thick rounds to ensure even cooking.
In a small mixing bowl, whisk together the olive oil, minced garlic, dried rosemary, dried thyme, sea salt, and black pepper.
Place the chicken breast on one side of the baking sheet and arrange the sliced root vegetables on the other side in a single layer.
Brush half of the garlic-herb oil over the chicken breast and drizzle the remaining half over the vegetables, tossing them to coat thoroughly.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden brown.
Remove from the oven and let the chicken rest for 5 minutes to lock in the juices before slicing and serving with the roasted vegetables.