Preheat oven to 400°F. Line a sheet pan with parchment and pat cod fillets dry with paper towels.
In a small bowl, whisk together olive oil, lemon juice, lemon zest, garlic powder, paprika, salt, and black pepper.
Place cod on the prepared pan and brush all over with the lemon-garlic mixture. Let sit for 5 minutes while the oven finishes heating.
Bake for 12 to 15 minutes, until the fish flakes easily with a fork and reaches an internal temperature of 145°F.
Optional: Broil for 1 to 2 minutes for light color on top, watching closely.
Remove from the oven, sprinkle with parsley, and serve immediately.
Notes
For best results, thaw frozen cod overnight and pat very dry. Thickness will affect cook time—thicker fillets may need an extra 2 to 3 minutes. Swap paprika for smoked paprika for a hint of smokiness, or add a pinch of red pepper flakes for heat.