Place the cod fillets in a roasting dish or baking dish coated with olive oil. Drizzle with olive oil and season. Place the halved tomatoes, basil leaves and the sliced mozzarella cheese on the fillets. Sprinkle the parmesan on top and drizzle again with olive oil.
Bake in the hot oven on the top shelf for about 15 to 20 minutes until golden brown.