Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Pat the cod fillet dry with a paper towel to ensure a better texture and place it on one side of the prepared baking sheet.
Trim the woody ends off the asparagus spears and arrange them in a single layer on the other side of the baking sheet.
In a small glass bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, and dried oregano until well combined.
Drizzle the lemon-herb mixture evenly over both the cod and the asparagus, using a brush or spoon to coat the fish thoroughly.
Sprinkle the sea salt and black pepper over the fish and vegetables.
Bake for 12 to 15 minutes, or until the cod is opaque and flakes easily with a fork and the asparagus is tender-crisp.
Place the warm cooked quinoa in a shallow bowl or plate, top with the roasted asparagus and cod, and garnish with freshly chopped parsley.