Prepare the Salted Cod: Begin by soaking the salted codfish in approximately 2 quarts of cold water. Change the water every two to three hours for a total of 8 hours to gradually remove the excess salt and soften the fish. After soaking, drain the cod and cut it into bite-sized pieces.
Assemble the First Layer: In a large pot, create the first layer by placing half of the sliced potatoes evenly on the bottom. Follow with half of the cod pieces, then layer half of the sliced onions, and then half of the sliced hard-boiled eggs. Sprinkle half of the capers and minced garlic evenly over the top. Add half of the green olives and roasted red peppers. Finish this layer with half of the golden raisins, then gently place the bay leaf on top.
Add Sauces and Oil: Pour half of the tomato sauce and half of the olive oil over this layered mixture, allowing the liquids to seep through the layers for rich flavor infusion.
Repeat the Layering: Repeat the exact layering sequence with the remaining potatoes, cod, onions, eggs, capers, garlic, olives, roasted peppers, and raisins—this time without adding a bay leaf.
Add Liquids and Cook: Carefully pour the water and white wine over the layers, ensuring you do not stir or disturb the arrangement. Cover the pot with a tight-fitting lid and bring the mixture to a gentle boil over medium heat.
Simmer to Perfection: Once boiling, reduce the heat to medium-low and let the stew simmer uncovered for about 30 minutes, or until the potatoes become tender and all flavors meld together beautifully.