Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and chop the carrots, parsnips, and red onion into uniform 1-inch pieces to ensure even roasting.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a large bowl, toss the chopped root vegetables with 1 teaspoon of olive oil, half of the garlic, half of the herbs, and a pinch of salt and pepper.
Pat the chicken breast dry with a paper towel, then rub with the remaining teaspoon of olive oil, garlic, herbs, salt, and pepper.
Spread the vegetables in a single layer on the prepared baking sheet and place the chicken breast in the center.
Roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and lightly caramelized.
Let the chicken rest for 5 minutes before slicing to keep it juicy, then serve alongside the roasted vegetables.