Preheat your oven to 400°F 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 glass bowl, whisk together the extra virgin olive oil, the juice of half a lemon, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast, halved potatoes, and asparagus on the prepared baking sheet in a single layer.
Drizzle the lemon-herb dressing over the chicken and vegetables, using your hands or tongs to toss everything until thoroughly and evenly coated.
Arrange the lemon half on the tray to roast alongside the meal for extra juice later.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender and golden.
Remove from the oven, let the chicken rest for 5 minutes to lock in the juices, then squeeze the roasted lemon over the entire tray before serving.