Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Trim the woody ends off the asparagus and place them on one side of the baking sheet.
Pat the cod fillet dry with a paper towel and place it on the other side of the baking sheet.
In a small bowl, whisk together the olive oil, juice from the half lemon, dried oregano, garlic powder, sea salt, and black pepper.
Drizzle half of the herb oil over the cod and the remaining half over the asparagus, tossing the asparagus to coat evenly.
Bake for 12 to 15 minutes, or until the cod is opaque and flakes easily with a fork and the asparagus is tender.
Fluff the pre-cooked quinoa and place it in a serving bowl.
Top the quinoa with the baked cod and asparagus, then garnish with freshly chopped parsley before serving.