Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Pat the chicken breast completely dry with a paper towel to ensure the herbs stick and the meat develops a golden exterior.
In a small bowl, whisk together 0.5 tbsp of the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast on the prepared baking sheet and brush it thoroughly with half of the lemon-herb marinade.
Roast the chicken in the center of the oven for 10 minutes to give it a head start on cooking.
While the chicken is roasting, toss the trimmed asparagus spears with the remaining 0.25 tbsp of olive oil and a tiny pinch of salt.
Remove the pan from the oven, add the asparagus around the chicken, and drizzle the remaining marinade over both.
Return the pan to the oven for another 10-12 minutes until the chicken reaches an internal temperature of 165°F and the asparagus is vibrant and tender.
Allow the chicken to rest for 5 minutes before slicing it and serving over a bed of warm, fluffy cooked quinoa.