Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Halve the baby potatoes and place them on one side of the sheet pan. Drizzle with half of the olive oil and sprinkle with a portion of the salt, pepper, and chopped rosemary.
Roast the potatoes for 10 minutes to give them a head start.
While potatoes roast, mince the garlic and finely chop the remaining rosemary and thyme.
Remove the pan from the oven. Place the chicken breast and trimmed asparagus on the pan. Drizzle everything with the remaining olive oil.
Rub the minced garlic, rosemary, thyme, salt, and pepper onto the chicken and toss the asparagus to coat.
Return the pan to the oven and roast for 15-20 minutes, or until the chicken reaches an internal temperature of 165°F and the asparagus is tender.
Drizzle fresh lemon juice over the chicken and vegetables before serving for a bright, clean finish.