The thing to remember here is that good-quality tinned salmon makes better fishcakes than fresh, so don't be tempted to cook some salmon just for this.
This recipe is from Delia's Complete How to Cook. Makes 12 (serves 6)
First of all boil the potatoes in salted water for about 25 minutes or until they're absolutely tender when tested with a skewer.
(Be careful, though – if they are not tender you will get lumps.) Then drain the potatoes and mash them to a purée with the mayonnaise using an electric hand whisk, then add some seasoning. Now, in a large mixing bowl, simply combine all the ingredients for the fishcakes together. Mix really thoroughly, then taste and season again if it needs it. After that, allow it to cool thoroughly, then cover the bowl and place it in the fridge, giving it at least 2 hours to chill and become firm.
When you are ready to cook the fishcakes, lightly flour a work surface, then turn the fish mixture on to it and, using your hands, pat and shape it into a long roll, 2-2½ inches (5-6 cm) in diameter. Now cut the roll into 12 round fishcakes, pat each one into a neat, flat shape and then dip them, one by one, first into the beaten egg and then into the matzo meal (or breadcrumbs), making sure they get a nice, even coating all round.
Now, in a large frying pan, heat the oil and butter over a high heat and, when it is really hot, add half the fishcakes to the pan, then turn the heat down to medium and give them 4 minutes' shallow frying on each side. Then drain on crumpled greaseproof paper and keep warm. Repeat with the rest of the fishcakes, adding a little more oil and butter if needed.
Serve immediately on hot plates with English Parsley Sauce (which you can watch being made in our Cookery School Video, just click on the image to play), sprigs of parsley and some lemon wedges.