In Portugal, you'll find as many variations on this recipe as there are home cooks, and you should feel free to adapt this recipe to make it your own, too. They all take advantage of the natural affinity that the main ingredients have for one another, namely cod and potatoes, and the usual seasoning base of onion and garlic. This recipe also uses another component that's often included: cornbread that's crushed and used as the breadcrumbs in the topping, which turns delightfully golden and crisp in the oven.