Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Wash and halve the baby potatoes, and trim the woody ends off the asparagus spears.
In a small bowl, whisk together the extra virgin olive oil, minced garlic, dried rosemary, sea salt, and black pepper.
Place the chicken breast and halved baby potatoes on the prepared baking sheet and drizzle with two-thirds of the garlic-herb oil mixture, tossing to coat evenly.
Roast in the center of the oven for 15 minutes.
Remove the tray from the oven, add the asparagus spears to the empty spaces, and drizzle them with the remaining garlic-herb oil.
Return the tray to the oven and roast for an additional 10-12 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender.
Drizzle the fresh lemon juice over the chicken and vegetables before serving warm.