Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Peel and slice the carrots and parsnips into 1/2-inch thick rounds, and roughly chop the red onion.
Mince the garlic cloves finely.
In a large mixing bowl, combine the chicken breast, sliced carrots, parsnips, and red onion.
Drizzle with extra virgin olive oil and add 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 spices.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the chicken is not covered by vegetables.
Roast for 25 to 30 minutes, or until the chicken reaches an internal temperature of 165°F and the root vegetables are fork-tender.
Remove from the oven and let the chicken rest for 5 minutes before slicing to keep it juicy.
Plate the sliced chicken alongside the roasted vegetables and serve warm.