Preheat your oven to 400 degrees F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Peel and chop the carrots and parsnips into 1-inch chunks, and slice the red onion into thick wedges.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large mixing bowl, combine the chicken breast, chopped vegetables, olive oil, minced garlic, herbs, sea salt, and black pepper.
Toss everything thoroughly until the chicken and vegetables are evenly coated in the oil and aromatics.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the chicken pieces have space around them for even browning.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165 degrees F and the vegetables are golden and tender.
Let the chicken rest for 5 minutes before serving to ensure the juices redistribute for maximum tenderness.