Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Peel the carrots and parsnips, then slice them into 1-inch thick rounds or chunks to ensure even roasting.
In a large mixing bowl, whisk together the extra virgin olive oil, minced garlic, chopped rosemary, thyme, sea salt, and black pepper.
Add the chicken breast and the prepared root vegetables to the bowl, tossing thoroughly until every piece is coated in the herb oil mixture.
Arrange the chicken and vegetables in a single layer on the baking sheet, ensuring they are not overcrowded so they roast rather than steam.
Place the sheet in the oven and roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are fork-tender.
Remove from the oven and immediately drizzle the fresh lemon juice over the chicken and vegetables.
Let the chicken rest for 5 minutes before slicing to keep the juices intact, then serve alongside the roasted vegetables.