Sift the flour into a bowl. Make a well in the centre with your fist and add the egg. Mix with a fork and gradually add milk, until the batter is smooth. Add sugar, salt, pepper and sweetcorn and mix well.
Heat oil in a frying pan and add 1 tablespoon of the batter for each corn fritter. Fry over medium-low heat on each side for a few minutes, until the fritters are golden brown. Take out of the pan and place on kitchen paper.
Place the fritters onto a lightly greased baking tray and sprinkle with Gruyere cheese.
Pop under the grill for about 5 minutes until the cheese is melted and golden brown.