Smoked mackerel fishcake with celeriac remoulade Author: Graham Sharp Serves: 2 Ingredients [b]For the mackerel fishcake:[/b] 400g mashed potato (4 large baking potatoes) 100g butter salt and pepper 500g smoked mackerel 2 shallots, peeled, finely diced 4 tbsp chives, chopped 4 tbsp flat leaf parsley, chopped 1 lemon, zested 100g flour 3 eggs, beaten 100g