Soak salt cod for 24 hours in cold water, changing the water
3 times. Drain and place salt cod in a large pan. Cover with cold water, and bring to the boil. Lower heat and poach gently for 15 to 20 minutes. Drain fish, reserving the cooking liquid. Peel off skin and use your fingers to shred the fish into small flakes, removing all bones.
Trim leeks, wash well and cut into 5 cm