Soak the cod in cold water for 24 hours, changing the water four times during this time period.
Preheat the oven to 180 degrees C.
Cook the cod in milk over medium heat for 10 minutes. Remove cod with a slotted spoon and transfer to a greased ovenproof dish. Cook the potatoes in the same milk for 8 minutes (do not let them get too soft).
In a separate pan, heat oil over medium heat and gently cook the onion and garlic until golden brown. Add green capsicum, bay leaf and wine; cook over medium heat for 5 minutes. At this point, taste the sauce and season with salt and pepper to taste.
Arrange potatoes in baking dish around fish and cover it with the onion mixture. Bake for 30 minutes. Sprinkle chopped parsley on top before serving.