01 - Preheat oven to 400°F. Lightly grease a baking dish sufficient to accommodate the cod fillets in a single layer.
02 - Gently pat the cod fillets dry with paper towels, then arrange them in the prepared baking dish.
03 - In a small mixing bowl, thoroughly whisk together the melted unsalted butter, extra virgin olive oil, fresh lemon juice, lemon zest, minced garlic, chopped fresh parsley, salt, and fresh black pepper.
04 - Evenly pour the prepared lemon butter sauce over each cod fillet in the baking dish.
05 - Bake in the preheated oven for 15 to 20 minutes, or until the cod appears opaque throughout and flakes effortlessly with a fork.
06 - Garnish the baked cod with fresh lemon slices and additional chopped parsley just before serving.