Preheat the oven to 200 degrees.
Heat 3 tablespoons of the butter in a large (12-inch) sauté pan over medium-high heat. Add the onion, celery, and bell pepper and cook over medium heat for 8 to 10 minutes, stirring occasionally, until tender. Place the fish on top of the vegetables and add the cream, 1 teaspoon salt, and 1/2 teaspoon black pepper. Bring to a boil, lower the heat, cover, and simmer for 6 to 12 minutes (depending on the thickness of the cod), until the fish is just cooked. Set aside in the pan for 10 minutes, then flake the fish in large pieces with a fork.
Put 2 cups of the panko in a large bowl. Add the cod mixture, including the cooking liquid, the dill, mayonnaise, mustard, lemon zest, eggs, lobster, 2 teaspoons salt, and 1 teaspoon black pepper and mix gently.
Using a 2 1/4-inch ice cream scoop as a measure, shape the mixture into 14 (3-inch) fish cakes. Place the remaining 2 cups of panko on a plate and coat the cakes all over, patting the coating to adhere. Wipe the sauté pan clean with a paper towel and heat 2 tablespoons of the butter and 2 tablespoons of oil in the pan over medium heat. Place 5 cakes in the pan and cook for 5 minutes on each side, until nicely browned on both sides. Transfer the cakes to a sheet pan and keep them warm in the oven for up to 15 minutes. Repeat, adding more butter and oil, until the entire mixture is cooked. Serve hot with the Rémoulade Sauce.
Place the mayonnaise, cornichons, mustard, vinegar, 1 1/2 teaspoons salt, and 3/4 teaspoon pepper in the bowl of a food processor fitted with the steel blade. Pulse a few times until the cornichons are finely chopped (not pureed). Transfer to a sealed container and refrigerate.
This recipe has been updated and may differ from what was originally published or broadcast.
"Cooking for Jeffrey" by Ina Garten © Clarkson Potter 2016. Provided courtesy of Ina Garten. All rights reserved.