This is a good, low cost, standby using ingredients probably already in your larder. Any mustard will do the trick, but we prefer Dijon. Any mayonnaise e.g. garlic mayo or chilli mayo. Any solid, non-crumbly cheese. Substitute to your heart's content according to what you have in and your own taste.
As a change they can be made into fishcakes by making them slightly larger and flattening them before coating in the breadcrumb mixture. Serve hot on oven bottom muffins or on burger buns.