Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Halve the baby potatoes and trim the woody ends off the asparagus spears.
In a small bowl, whisk together the olive oil, lemon juice, minced garlic, chopped rosemary, sea salt, and black pepper.
Place the chicken breast, halved potatoes, and asparagus on the prepared baking sheet.
Drizzle the herb oil mixture over the chicken and vegetables, tossing them thoroughly to ensure an even coating.
Arrange everything in a single layer, ensuring the chicken is not covered by the vegetables.
Roast for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are golden and tender.
Let the chicken rest for 5 minutes before slicing and serving alongside the roasted vegetables.