Preheat and Prepare: First things first, preheat your oven to 200°C (180°C fan). Lightly grease a 9x13 inch baking dish with the olive oil. This stops the delicate fish from sticking.

Arrange the Cod: Pat the cod fillets dry with a paper towel – this helps them to absorb the flavours better. Arrange the fillets in a single layer in the prepared baking dish, making sure not to overcrowd them. Season both sides generously with the salt and pepper.

Mix the Sauce: In a small bowl, whisk together the melted butter, minced garlic, lemon zest, lemon juice, and the chopped parsley. This vibrant mixture is where all the flavour comes from.

Pour Over the Fish: Pour this beautiful lemon garlic butter mixture evenly over the cod fillets. Then, pour the white wine or vegetable stock around the fish in the bottom of the dish. This will create the steam and the base of your sauce.

Top and Cover: Arrange the thin lemon slices on top of each cod fillet. This not only looks lovely but also infuses more citrus flavour as it cooks. Cover the baking dish tightly with aluminium foil. I find that sealing the edges well is crucial for trapping the steam.

Bake to Perfection: Place the dish in the preheated oven and bake for 12-15 minutes. The exact time will depend on the thickness of your fillets.

Final Grill (Optional but Recommended): After 12-15 minutes, carefully remove the foil. The fish should be opaque and starting to flake. If you like a little colour, switch the oven to the grill setting and grill for another 2-3 minutes, watching it closely, until the edges are just beginning to turn golden brown.

Rest and Garnish: Let the cod rest in the dish for a couple of minutes. This allows the juices to settle. Spoon some of the delicious pan sauce over the fillets, garnish with a little extra fresh parsley, and serve immediately.