Preheat your oven to 400°F and line a rimmed baking sheet with parchment paper for easy cleanup and even roasting.
Peel the carrots and parsnips, then slice them into uniform 1-inch rounds to ensure they cook at the same rate as the chicken.
Mince the garlic cloves finely and combine them in a small bowl with the dried rosemary, dried thyme, sea salt, and black pepper.
In a large mixing bowl, toss the sliced root vegetables with 0.25 tablespoons of olive oil and half of the prepared garlic-herb seasoning.
Pat the chicken breast completely dry with a paper towel and rub with the remaining 0.25 tablespoons of olive oil and the rest of the herb mixture.
Arrange the seasoned vegetables in a single layer on the baking sheet, placing the chicken breast in the center of the tray.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and golden.
Allow the chicken to rest for 5 minutes before slicing to ensure it stays juicy, then serve immediately with the roasted vegetables.