Preheat oven to 400°F and line a baking sheet with parchment paper for easy cleanup.
Combine dry quinoa with water in a small pot, bring to a boil, then simmer covered for 15 minutes.
Trim the tough ends from the asparagus and place them on one side of the prepared baking sheet.
Pat the cod fillets dry and place them on the other side of the sheet.
Whisk olive oil, lemon juice, minced garlic, oregano, salt, and pepper in a small bowl.
Pour the marinade over the fish and asparagus, ensuring the vegetables are well-coated.
Bake for 12 to 15 minutes until the cod is opaque and flakes easily with a fork.
Fluff the quinoa and serve as a base for the fish and asparagus, garnishing with fresh parsley.