Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel the carrot and parsnip, then slice them into half-inch rounds; halve the Brussels sprouts.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a mixing bowl, toss the prepared vegetables with half of the olive oil, half of the garlic, and a pinch of salt and pepper.
Rub the chicken breast with the remaining olive oil, garlic, rosemary, thyme, salt, and pepper until evenly coated.
Arrange the chicken and vegetables in a single layer on the baking sheet, ensuring they are not overcrowded.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly caramelized.
Remove from the oven and let the chicken rest for 5 minutes before slicing to ensure maximum juiciness.