Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel to ensure the herbs stick and the meat browns beautifully.
In a large mixing bowl, combine the broccoli florets, sliced carrots, and red onion wedges.
Drizzle half of the olive oil over the vegetables and season with half of the salt and pepper, tossing to coat evenly.
In a small ramekin, mix the remaining olive oil with minced garlic, chopped rosemary, and thyme.
Rub the garlic-herb mixture all over the chicken breast and place it in the center of the baking sheet.
Arrange the seasoned vegetables around the chicken in a single layer to ensure even roasting.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender-crisp.
Remove from the oven and squeeze the fresh lemon juice over the entire tray to brighten the flavors before serving.