Place the egg yolks and milk in a large bowl, sift over the flour, caster sugar and salt and mix well. Whisk the egg whites in a clean grease-free bowl until they form soft peaks. Fold into the flour mixture. Gently stir in the blueberries. Heat a little oil in a large frying pan. Drop three to four medium spoonfuls of the pancake mixture into the hot pan and cook for 2 mins until crisp and golden. Turn over and cook for a further 1 min until golden.
Transfer to a clean tea towel to keep warm. Cook the remaining batter in the same way to make 12 pancakes. Serve the warm pancakes stacked up and topped with soured cream and maple syrup.