Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Rinse the quinoa in a fine-mesh strainer, then combine it with 0.5 cup water in a small saucepan over medium-high heat.
Bring the quinoa to a boil, then reduce heat to low, cover, and simmer for 15 minutes until the water is absorbed.
Trim the woody ends off the asparagus spears and arrange them on one half of the prepared sheet pan.
Pat the cod fillets dry with a paper towel to ensure a good sear and place them on the other half of the pan.
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 season everything with sea salt and black pepper.
Bake for 12 to 15 minutes 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 it alongside the fish and vegetables, garnishing with fresh chopped parsley.