Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Wash the potato and cut it into 1-inch cubes. Trim the woody ends off the asparagus spears.
Mince the garlic cloves and finely chop the fresh rosemary and thyme leaves.
In a small bowl, whisk together the olive oil, minced garlic, rosemary, and thyme.
Place the potato cubes on one side of the sheet pan, drizzle with half of the herb oil mixture, and sprinkle with a pinch of salt and pepper.
Roast the potatoes for 15 minutes to give them a head start.
Season the chicken breast with the remaining salt and pepper, then coat it with half of the remaining herb oil.
Remove the pan from the oven, move the potatoes to make room, and place the chicken on the pan. Roast for 10 minutes.
Toss the asparagus with the last bit of herb oil and add it to the pan. Roast everything for another 10-12 minutes until the chicken reaches an internal temperature of 165°F.
Remove from the oven and squeeze the fresh lemon juice over the chicken and vegetables before serving.