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 uniform 1/2-inch thick rounds to ensure even cooking.
Mince the garlic cloves finely.
In a large mixing bowl, combine the chicken breast, sliced carrots, and parsnips.
Drizzle with olive oil and sprinkle with the minced garlic, rosemary, thyme, sea salt, and black pepper.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and seasonings.
Spread the mixture onto the prepared baking sheet in a single layer, ensuring the chicken is not covered by vegetables.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and lightly browned.
Remove from the oven and let the chicken rest for 5 minutes before slicing.
Serve the sliced chicken alongside the roasted root vegetables.