Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Rinse the quinoa under cold water, then combine it in a small saucepan with 0.66 cups of water; bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes until fluffy.
Trim the woody ends off the asparagus and place the spears on one side of the prepared baking sheet.
Place the cod fillets on the other side of the baking sheet, ensuring they are patted dry with a paper towel first.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, minced garlic, and dried oregano.
Drizzle the lemon-herb mixture evenly over both the cod and the asparagus, then sprinkle everything with sea salt and black pepper.
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 divide it between plates, topping with the baked cod and roasted asparagus.
Garnish with freshly chopped parsley and an extra squeeze of lemon if desired before serving.