To begin, soak the salted cod in cold water overnight, changing the water at least twice. This ensures the fish is tender and not overly salty. Transition to cooking the fish.
Drain the soaked cod and place it in a saucepan with fresh water. Bring to a simmer and cook for 10 minutes until the fish flakes easily. Drain well, then flake the fish into small pieces. Move on to the potatoes.
Place the cubed potatoes in salted water and boil until tender, about 15 minutes. Drain thoroughly and mash until smooth. Prepare to combine with the cod.
In a large bowl, combine the flaked cod with the mashed potatoes. Stir gently to ensure even distribution. This forms the base of the cakes. Next, add flavourings.
Mix in the chopped onion, egg, melted butter, parsley, flour, and black pepper. Stir until the mixture holds together but avoid over mixing, which can make the cakes dense. Move to shaping.
With lightly floured hands, shape the mixture into patties about 2 cm thick. Place them on a tray and chill in the fridge for at least 20 minutes to firm up. Proceed to frying.
In a heavy skillet, heat butter or oil over medium heat. Fry the fish cakes for 3–4 minutes per side until golden brown and crisp. Cook in batches to avoid overcrowding. Transition to draining.
Transfer cooked fish cakes onto a plate lined with kitchen paper to absorb excess oil. Keep warm while finishing the remaining cakes. Move to the final serving step.
Arrange the salt fish cakes on a platter and serve with pickled beets, baked beans, or chow chow for a traditional Nova Scotian touch. Presentation tip: a squeeze of lemon adds brightness to the rich flavour.