Preheat your oven to 400°F and line a large sheet pan with parchment paper for easy cleanup.
Prepare the asparagus by snapping off the tough, woody ends and mincing the garlic clove finely.
In a small mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, dried oregano, sea salt, and black pepper.
Pat the cod fillet completely dry with a paper towel and place it on one side of the prepared baking sheet, then arrange the asparagus in a single layer on the other side.
Brush the lemon-herb marinade generously over the top of the cod and drizzle the remaining mixture over the asparagus, tossing the spears gently to ensure they are well-coated.
Bake for 12 to 15 minutes, or until the cod is opaque and flakes easily with a fork and the asparagus is vibrant and tender-crisp.
Transfer the roasted cod and asparagus to a plate and serve immediately alongside the warm, cooked quinoa.