Chef Michael Serpa, Neptune Oyster Bar, Boston Serves 6 to 8
1 pound dried salt cod fillet 1 cup plus 1 tablespoon extra virgin olive oil 4 cloves garlic, minced 1 small onion, diced 1 leek, white part only, diced 8 russet potatoes, peeled and cut into large dice 1 sprig rosemary 1 pound fresh cod scraps 1 cup white wine 2 cups whole milk ½ cup heavy cream, warmed kosher salt freshly ground black pepper
Soak the dried salt cod in water for at least 24 hours, then rinse and set aside.
In a heavy skillet, heat 1 T olive oil and add the garlic. Saute 1-2 minutes, then add onions and leeks. In another pan, cover the potatoes with cold water and 1 tablespoon salt. Bring to a boil, reduce heat and simmer until tender.
When the onions and leek have softened, add the sprig of rosemary, cook for 1-2 minutes, then remove it from the pan. Add the rinsed salt cod and fresh cod scraps, cook for 2 minutes, then add the wine. Bring to a simmer and reduce wine by half, then add the milk and simmer everything together for 15 minutes.
When the potatoes are tender, drain and return to their pot. Using a slotted spoon, strain out the fish and onions into the bowl of a food processor, reserving the broth, and purée. Add the broth, remaining cup of olive oil, and warm heavy cream to the potatoes and mash (you can also run this through a ricer or food mill for a smoother baccalà). Add the puréed fish to the potatoes and more cream or olive oil, if needed. Add freshly ground black pepper to taste, and more salt if desired.
Serve warm with toasted crostini.