Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and slice the carrots into rounds, cube the parsnips, and cut the red onion into thick wedges.
In a large mixing bowl, toss the carrots, parsnips, and onion with half of the olive oil, half of the sea salt, and half of the black pepper.
Mince the garlic cloves and combine them in a small bowl with the remaining olive oil, rosemary, thyme, and the rest of the salt and pepper.
Rub the garlic-herb mixture evenly over all sides of the chicken breast.
Spread the seasoned vegetables across the prepared baking sheet and nestle 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 golden.
Allow the chicken to rest for 5 minutes before slicing it against the grain and serving with the roasted root vegetables.