Mix egg and white with polenta, salt and half the sour cream. Stir in corn. Stand 10 minutes. Mix in spring onions and oysters.
Heat a little oil or butter in a frying pan and dollop in small spoonfuls of mixture, allowing one oyster per fritter. Cook until fritters begin to firm slightly then flip and cook no more than 10 seconds – you don’t want to overcook the oysters. Flip back over and place on a platter or in their own shells which have been washed well and warmed slightly. Dollop remaining sour cream on top of each fritter then sprinkle with the chives. Eat while still warm.