Preheat 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; cut the red onion into wedges.
In a large bowl, toss the vegetables with 0.5 tbsp of olive oil, half the minced garlic, half the herbs, and a pinch of salt and pepper.
Spread the vegetables in a single layer on the prepared sheet pan.
Rub the chicken breast with the remaining 0.5 tbsp of olive oil, garlic, rosemary, thyme, salt, and pepper.
Place the chicken in the center of the sheet pan, nestled among the vegetables.
Roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden.
Let the chicken rest for 5 minutes before slicing and serving with the roasted root vegetables.