Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Wash and halve the baby potatoes, and trim the tough, woody ends off the asparagus spears.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast and halved potatoes in a large mixing bowl and pour over two-thirds of the lemon-herb marinade, tossing to coat thoroughly.
Arrange the chicken and potatoes on the prepared sheet pan in a single layer, ensuring they are not overcrowded.
Roast in the oven for 15 minutes.
While the chicken is roasting, toss the asparagus in the remaining marinade.
Remove the pan from the oven, add the asparagus to the sheet pan, and return to the oven for an additional 10 to 12 minutes.
Check that the chicken has reached an internal temperature of 165°F and the potatoes are fork-tender and golden.
Let the chicken rest for 5 minutes before serving to ensure it stays juicy.