Peel the potatoes (1) and divide into two parts (2), then into slices (3). Leave aside on a plate.
Line the bottom of a baking tray (4) with a kitchen foil and place on it a portion of the potatoes (5), leaving the rest aside. Add some salt to the potatoes (6).
Sprinkle with black pepper (7) and add three tablespoons of extra virgin olive oil (8). Then bake the tray in a preheated oven at 150°C for about 15 minutes (9).
Then remove the tray from the oven (10) and and place on the cod fillets (11) adding salt to your liking (12).
Top the cod fillets with the rest of the potatoes (13) up to cover both fillets (14) and then add some salt to the potatoes (15).
Sprinkle with freshly ground black pepper (16) and add two tablespoons of extra virgin olive oil (17). Bake in preheated oven at 150°C for about thirty minutes (18). Once cooked, take off from the oven and serve still hot.