Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Pat the chicken breast dry with a paper towel to ensure a golden sear during roasting.
In a large bowl, toss the chopped carrots, parsnips, and red onion with half of the olive oil, sea salt, and black pepper.
In a small bowl, whisk together the remaining olive oil, minced garlic, rosemary, thyme, and lemon juice.
Rub the garlic-herb mixture evenly over both sides of the chicken breast.
Arrange the chicken and vegetables in a single layer on the prepared baking sheet.
Roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender and slightly browned.
Let the chicken rest for 5 minutes before slicing to keep it juicy.