My Mum used to make these often when I was young. she had no real recipe so they were always different but always so good. just use mashed potato as a base but please don't add butter or milk as mix will be unsusable for the patties (been there,done that) add tuna, onion, carrot to the mashed potato. add seasoning and form into. patties, coat in breadcrumbs if desired before frying.......salmon also works well.