Wash the potatoes, wrap them in foil and put them to be toasted in the oven until tender. Then peel and mash them. Salt and bake the fish in an oven preheated to 356°F (180 °C).
Place in a suitable container in the refrigerator for 1 hour or in the freezer for 30 minutes. Heat a pan, put the meatballs in fat and fry on both sides until reddish.