How to Make It
Heat oven to 450° F. Place the cod on a baking sheet and sprinkle with the chili powder, oregano, and ½ teaspoon salt.
Bake the cod until opaque throughout, 10 to 12 minutes. Let cool. Flake into small pieces with a fork.
Meanwhile, in a food processor, process the bread until fine crumbs form. Pour onto a sheet of wax paper.
In a medium bowl, whisk together the mayonnaise, egg, and 1 tablespoon of the lime juice. Add the flaked cod, celery, and ¼ teaspoon salt and com-bine. Tightly pack the mixture into 8 patties. Gently place each patty in the bread crumbs and turn to coat evenly.
Heat the oil in a large, heavy skillet over medium heat. Place 4 fish cakes in the skillet and cook until the crumbs are golden brown, about 5 minutes per side (turn carefully). Transfer to a plate and repeat with the remaining fish cakes, adding more oil as necessary.
Meanwhile, combine the sour cream, chipotle, remaining 2 tablespoons lime juice, zest, sugar, and ¼ teaspoon salt. Serve with the fish cakes.