Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Snap off the tough, woody ends of the asparagus spears and spread them across one half of the prepared baking sheet.
Pat the cod fillets dry with a paper towel and place them on the other half of the sheet.
In a small glass jar or bowl, whisk together the olive oil, lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Drizzle the lemon-herb mixture evenly over both the cod and the asparagus, using your hands or a brush to ensure the fish is well-coated.
Roast in the oven for 12 to 15 minutes, or until the cod is opaque and flakes easily with a fork and the asparagus is tender.
Transfer the roasted cod and asparagus to a plate alongside the warm cooked quinoa.
Garnish with a sprinkle of fresh chopped parsley and an extra squeeze of lemon if desired before serving.