Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Rinse the quinoa under cold water, then combine it in a small pot with 0.66 cups of water; bring to a boil, then reduce to a simmer, cover, and cook for 15 minutes.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the cod fillet and the trimmed asparagus spears onto the prepared baking sheet.
Drizzle the lemon-herb marinade over the fish and the asparagus, using a brush or spoon to ensure the cod is evenly coated.
Bake in the center of the oven for 12 to 15 minutes, or until the cod is opaque and flakes easily with a fork and the asparagus is tender-crisp.
Fluff the cooked quinoa with a fork and plate it alongside the roasted cod and asparagus.
Garnish the entire dish with freshly chopped parsley and an extra squeeze of lemon if desired before serving.