Make these cod cakes for a tapas party or to serve with a salad or braised greens for a family supper. You can even form the cakes ahead of time, refrigerate (covered), and then fry off just before serving. These traditional cakes are simply made with cod, potatoes, and seasonings, with an egg as the binder. The potatoes need to be boiled first and then mashed or pureed, and this, too, can be done in advance.