Preheat your oven to 400°F and line a large baking sheet with parchment paper.
In a small bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, chopped rosemary, sea salt, and black pepper.
Place the chicken thighs and halved baby potatoes in a large mixing bowl and pour over two-thirds of the lemon-herb mixture, tossing until well coated.
Spread the chicken and potatoes in a single layer on the prepared baking sheet, ensuring they are not overcrowded.
Roast in the oven for 15 minutes, then remove the pan and add the trimmed asparagus spears to the empty spaces.
Drizzle the remaining lemon-herb mixture over the asparagus and return the pan to the oven for another 10 to 12 minutes.
Cook until the chicken reaches an internal temperature of 165°F and the potatoes are fork-tender and golden brown.
Serve the chicken and vegetables immediately, drizzling any remaining juices from the pan over the top.