Place the salt cod in a large bowl and cover completely with cold water. Leave to soak for at least 12 hours, draining and covering with fresh water every few hours. When you’re ready to cook, finely slice the parsley stalks (reserving the leaves). Peel the shallots and finely slice into rounds. Using a speed-peeler, peel away strips of lemon zest. Place a large pan on a high heat, half fill with water and bring to the boil, then reduce to a simmer. Drain and add the salt cod, then the parsley stalks, shallots and lemon peel. Poach for around 20 minutes, or until the cod starts to soften and flake apart. Meanwhile, peel and finely slice the onions, then place in a large, wide pan on a medium heat with 2 tablespoons of olive oil. Season with black pepper and cook for 15 to 20 minutes, or until golden and starting to caramelize, stirring regularly. Destone the olives and tear the flesh into a bowl. Roughly chop the parsley leaves, and add half to the bowl with the chilli flakes, vinegar and 4 tablespoons of extra virgin olive oil. Mix well and set aside. Use a slotted spoon to remove the salt cod to a plate. Pick out any bones, then break the flesh into the onion pan, also adding a good splash of poaching liquid. Cook for a further 10 minutes on a low heat, or until the fish is soft and flaking apart, stirring occasionally. Turn the heat off. Meanwhile, peel the potatoes, then finely slice into matchsticks using a mandolin (use the guard!) or a sharp knife. Just under half fill a sturdy pan with the vegetable oil – the oil should be 8cm deep, but never fill your pan more than half full – and place on a medium-high heat. Use a thermometer to tell when it’s ready (170°C), or add a piece of potato and wait until it turns golden – that’s the sign that it’s ready to go. Working in batches, use a slotted spoon to carefully lower the potato matchsticks into the hot oil to cook for 1 to 2 minutes, or until very lightly golden, but not cooked through. Transfer to a double layer of kitchen paper to drain and repeat. Return the cod mixture to a medium heat, then stir in most of the remaining chopped parsley. Beat the eggs, then gently stir them into the pan. Fold in three-quarters of the potato matchsticks and take the pan off the heat – the eggs will continue to cook in the pan, so make sure you don’t overcook them at this stage. Return the remaining potato matchsticks to the hot oil to fry for a further 2 to 3 minutes, or until golden and cooked through. Transfer to a double layer of kitchen paper to drain, and season with sea salt. Transfer the bacalhau to a serving dish and top with the crispy potato fries. Using a slotted spoon, spoon over the marinated olives, then sprinkle the remaining chopped parsley on top. Great served with a green salad and a cold glass of dry white wine.