Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Peel and slice the carrots and parsnips into half-inch rounds, and cut the red onion into thick wedges.
In a mixing bowl, toss the vegetables with half of the olive oil, half of the sea salt, and half of the black pepper.
Mince the garlic and finely chop the fresh rosemary and thyme.
Rub the chicken breast with the remaining olive oil, minced garlic, rosemary, thyme, and the rest of the salt and pepper.
Spread the seasoned vegetables onto the baking sheet and place the chicken breast in the center.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.