Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Peel and chop the carrots and parsnips into 1-inch chunks, and slice the red onion into thick wedges.
In a large mixing bowl, whisk together the extra virgin olive oil, minced garlic, dried rosemary, dried thyme, sea salt, and black pepper.
Add the chicken breast and the prepared vegetables to the bowl, tossing thoroughly until every piece is coated in the herb oil.
Arrange the chicken and vegetables in a single layer on the prepared baking sheet, ensuring they are not overcrowded to allow for even browning.
Roast in the center of the oven for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are fork-tender and golden.
Remove from the oven and let the chicken rest for 5 minutes before slicing it against the grain to maintain juiciness.
Serve the sliced chicken alongside the roasted root vegetables, drizzling any remaining pan juices over the top.