Saute the chopped onion in the margarine. Add the well drained tuna and stir well  Add the flour, mix well and add the milk.
Season to taste with salt and pepper and finally add the finely chopped parsley.
Make small balls with this dough, go through flour, then egg and finally the breadcrumbs and fry them.

You can fry or freeze them to fry at another time.

Recipe & Photo Credit: Guida, asminhasreceitas-guida.blogspot.pt