Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken breast on one side of the sheet pan and brush thoroughly with half of the lemon-herb marinade.
Roast the chicken alone for 10 minutes to ensure it cooks through at the same time as the vegetables.
While the chicken is starting, trim the woody ends off the asparagus and toss the spears and cherry tomatoes with the remaining marinade.
Remove the pan from the oven, arrange the asparagus and tomatoes in a single layer next to the chicken, and return to the oven for another 12-15 minutes.
Once the chicken reaches an internal temperature of 165°F and the vegetables are tender, remove from the oven.
Plate the roasted chicken and vegetables over a bed of warm, fluffy quinoa and garnish with freshly chopped parsley.