Put the flour and baking powder in a mixing bowl, make a well in the centre, add the egg and a little milk and mix to a smooth paste. Slowly add the rest of the milk and beat to a smooth batter. Stir in 1 tablespoon of the caster sugar.
Lightly oil a frying pan and heat. Drop a large tablespoonful of mixture onto the hot pan, cook for 2-3 minutes until golden brown underneath and almost set on top, turn over and cook other side until golden. Keep warm while making remaining pancakes.
Melt butter in small frying pan and fry the apple slices until golden. Add remaining sugar and stir until dissolved. Serve with the pancakes.