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 with 0.5 cup of water in a small saucepan; bring to a boil, reduce to low, cover, and simmer for 15 minutes.
While the quinoa cooks, finely mince the garlic and roughly chop the fresh parsley.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, minced garlic, parsley, sea salt, and black pepper.
Trim the woody ends off the asparagus and place them on one side of the prepared baking sheet, then place the cod fillets on the other side.
Drizzle the lemon-herb marinade evenly over both the cod and the asparagus, using a brush or spoon to ensure the fish is well coated.
Bake 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 serve as a base for the baked cod and roasted asparagus.