Check the fish carefully for any pin-bones, removing any you find with tweezers. If using smoked haddock, poach it in gently simmering milk or water to cover for 3-4 minutes, then drain and break up the flesh into fairly large pieces.
Heat the butter in a pan and gently cook the leek for 3-4 minutes until soft, then add the cream and fish.
Season lightly and simmer until the cream has reduced down a little and is just coating the fish. Taste and adjust the seasoning if necessary.
Meanwhile, soft-boil the bantam eggs by carefully lowering them into a pan of simmering water and cooking gently for3 ½ – 4 minutes. Briefly refresh in cold water until the eggs are cool enough to handle, then remove and carefully peel.
Divide the creamed fish and leek among warmed-up plates and sprinkle with the chopped parsley and place the egg on top. Grind over a little pepper and serve at once.