Preheat your oven to 200°C (400°F). Line a 9x13 inch baking dish with aluminium foil, leaving enough overhang to fold over later. The foil makes cleanup effortless — you'll simply lift it out and throw it away.

Pat the cod fillets dry with kitchen paper. This step is crucial; excess moisture creates steam rather than allowing the fish to bake properly. The fillets should feel dry to the touch before you season them.

In a small mixing bowl, combine the olive oil, minced garlic, lemon zest, lemon juice, parsley, dill, oregano, salt, and pepper. Stir until the herbs are evenly distributed — you'll smell the bright, fresh aroma of lemon and herbs coming together.

Place the cod fillets in the prepared baking dish, spacing them about 2cm apart. Pour the herb mixture evenly over each fillet, using a spoon to ensure every piece is well coated. The fish should glisten with the oil and herbs.

Drizzle the melted butter over the top of the fillets. This adds richness and helps the fish develop a golden edge as it bakes. The butter will pool slightly around the fish.

Fold the foil over the fish to create a sealed packet, then bake for 15-18 minutes. The exact time depends on the thickness of your fillets. You'll know it's done when the fish flakes easily with a fork and the flesh has turned from translucent to opaque white throughout. The aroma of lemon and herbs will fill your kitchen.

Remove from the oven and carefully open the foil packet — watch out for the steam. Garnish with fresh lemon slices and an extra sprinkle of parsley if desired. Serve immediately while the fish is still warm and flaky.