Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and chop the carrots and parsnips into 1-inch chunks, and slice the red onion into thick wedges.
Place the chicken breast and the prepared vegetables onto the baking sheet.
In a small bowl, whisk together the olive oil, minced garlic, rosemary, thyme, salt, and pepper.
Drizzle the herb oil over the chicken and vegetables, tossing everything by hand until thoroughly and evenly coated.
Spread the ingredients into a single layer, ensuring the chicken is not covered by vegetables.
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 tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.