Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Rinse the quinoa thoroughly in a fine-mesh strainer, then combine with 0.5 cup water in a small pot; bring to a boil, 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.
Pat the cod fillets dry with a paper towel and place them on the other side of the baking sheet.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, and chopped parsley.
Drizzle the lemon-herb mixture evenly over the cod and asparagus, then sprinkle both with sea salt and black pepper.
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 cooked quinoa with a fork and serve as a base for the roasted fish and vegetables.