To begin, place the salt cod in a large bowl and cover generously with cold water. Soak overnight, changing the water at least twice to remove excess salt while retaining the fish's characteristic flavour. Once soaked, move on to preparing the hard bread.

Drain the soaked cod and place it in a saucepan with fresh water. Bring to the boil over medium heat, then reduce the heat and simmer gently for about 15 minutes, or until the fish flakes easily. Drain well, transfer to a plate and separate the fish into large flakes. Set aside while you prepare the bread.

Place the soaked hard bread and enough of its soaking water to cover it in a saucepan. Heat slowly just until the water comes to the boil, then immediately remove the pan from the heat and drain well. Do not simmer the bread, as prolonged cooking can make it overly soft and gluey. Keep warm while you prepare the scrunchions.

Place the diced salt pork in a frying pan over medium to low heat. Cook slowly until the pieces are crisp and golden and plenty of fat has rendered into the pan. Do not discard the rendered fat, as it provides much of the traditional flavour of Fish and Brewis. Continue with the onions.

Add the chopped onions to the rendered pork fat and cook for about 5 minutes, stirring occasionally, until softened. Stir in the butter, if using, and allow it to melt into the pork fat. Once the onions are tender, prepare to combine the dish.

Place the flaked salt cod and drained hard bread together in a large pan or serving dish. Spoon the onions, scrunchions and rendered fat over the top, distributing them evenly. Gently combine everything without excessively breaking apart the softened bread.

Serve Fish and Brewis immediately while hot, spooning additional scrunchions and rendered fat over each portion. Traditionally, the combination of tender salt cod, softened hard bread and crisp pork provides plenty of flavour on its own, although mustard pickles or other Newfoundland style pickles can be served alongside for a sharp contrast.