Some left over mashed potato provided a good opportunity to put together a recipe for potato cakes with smoked mackerel. Beetroot goes surprisingly well with peppered smoked mackerel, helping 'cut' it like the horseraddish that's a frequent partner.
Skin the mackerel fillet and break it into pieces. Combine it with some chopped beetroot (about 25%), the mash (about 50%) and a squeeze of lemon juice and shape into cakes. Beat an egg and coat the cakes. Roll them in flour, and coat with egg again. Then roll in flour again. Fry in oil.
Goes well with red cabbage and apple.