Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Wash the baby potatoes and cut them into halves or quarters so they are uniform in size. Trim the tough, woody ends off the asparagus spears.
In a mixing bowl, toss the potatoes with half of the olive oil, half of the minced garlic, and a pinch of sea salt.
Spread the potatoes onto one side of the prepared sheet pan and roast for 15 minutes to give them a head start.
While the potatoes are roasting, season the chicken breast evenly with the remaining olive oil, garlic, chopped rosemary, sea salt, and black pepper.
Remove the pan from the oven, move the potatoes to one side, and place the chicken breast and asparagus on the other side.
Return the pan to the oven and roast for an additional 15 to 20 minutes, or until the chicken reaches an internal temperature of 165°F and the asparagus is tender.
Remove from the oven and immediately drizzle the fresh lemon juice over the chicken and vegetables to brighten the flavors before serving.