Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Peel and chop the carrots, parsnips, and red onion into uniform 1-inch pieces to ensure even roasting.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, toss the chopped vegetables with half of the olive oil, half of the minced garlic, half of the herbs, and a pinch of salt and pepper.
Rub the chicken breast with the remaining olive oil, garlic, rosemary, thyme, salt, and pepper.
Spread the seasoned vegetables across the baking sheet and place the chicken breast in the center, ensuring nothing is overcrowded.
Roast for 25 to 30 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 at least 5 minutes before slicing to keep it juicy.