Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Halve the baby potatoes and trim the tough, woody ends off the asparagus spears.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, chopped rosemary, sea salt, and black pepper.
Place the chicken breast and halved potatoes on the prepared baking sheet.
Drizzle half of the lemon-herb dressing over the chicken and potatoes, tossing the potatoes to ensure they are evenly coated.
Roast in the center of the oven for 15 minutes.
Remove the sheet from the oven, add the asparagus spears to the tray, and drizzle with the remaining herb dressing.
Return to the oven and roast for another 10-12 minutes until the chicken reaches an internal temperature of 165°F and the potatoes are golden and crispy.
Allow the chicken to rest for 5 minutes before slicing and serving alongside the roasted vegetables.