200g/7oz cooked beetroot (vacuum-packed is good, but not pickled)
1 tbsp chopped fresh chives
1 lemon, finely grated zest only
500g/1lb 2oz medium-sized potatoes, peeled and halved
1 small red onion, finely chopped
1 bunch spring onions, finely chopped
1 tbsp chopped fresh tarragon or flatleaf parsley
2 tbsp capers, drained
3 tbsp horseradish sauce
2 tbsp plain flour, seasoned with salt and freshly ground black pepper
salt and freshly ground black pepper
200g/7oz fresh breadcrumbs
2 tbsp olive oil
sunflower or vegetable oil, for shallow frying
2 free-range eggs, beaten
soured cream, to serve
500g/1lb 2oz smoked mackerel fillets