This is the quintessential Christmas Eve dish, but it works all winter. The key is the balance of salt. Since the Baccalà, Gaeta olives, and capers all carry brine, the tomato sauce must be prepared without any added salt. The fish seasons the sauce as it simmers. Because our fillets have no skin or bones, the fish stays in clean, meaty chunks that don't get lost in the tomatoes.
San Marzano Tomatoes: Only use whole peeled tomatoes that you crush by hand. The sauce needs that coarse texture to grab onto the fish.
Gaeta Olives: These are essential. Unlike standard black olives, Gaetas have a wine-like tartness that cuts through the salt of the cod.
Francesco's tip: Fry the fish in a mix of olive oil and a tablespoon of butter. The butter helps the flour brown faster, which adds a nutty flavor to the final red sauce.
1. Prepare the Fish: Cut the soaked fillet into 3-inch squares. Pat them completely dry. Dredge each piece in the flour, shaking off the excess so only a thin veil remains.
2. The Initial Sear: Heat the olive oil (and butter, per tip) in a wide, heavy-bottomed pan over medium-high heat. Fry the fish pieces for 2 to 3 minutes per side. You are not cooking them through; you are creating a golden seal so the fish doesn't turn into mush later. Remove the fish and set aside on a plate.
3. Build the Base: In the same pan, add the sliced garlic. Once it turns straw-colored, pour in the white wine. Scrape the bottom of the pan to release the browned flour bits from the fish. Let the wine reduce by half.
4. Simmer the Sauce: Add the hand-crushed tomatoes, olives, and capers. Bring to a boil, then lower the heat to a simmer. Cook the sauce for 15 minutes until it starts to darken and thicken.
5. Finish: Place the fried Baccalà pieces back into the sauce. Spoon some of the tomato mixture over the top. Cover the pan and simmer for another 5 to 7 minutes. The fish should flake easily with a fork but remain in whole pieces. Top with plenty of chopped parsley and black pepper before serving with crusty bread.
Even after a 48-hour soak, Baccalà retains a core of sea salt. As the fish simmers in the tomato sauce, it acts like a seasoning packet, releasing salt into the tomatoes. Between the fish, the capers, and the olives, adding extra salt at the beginning will make the dish inedible. Taste the sauce only in the final 2 minutes of cooking and adjust only if necessary.