Separate the egg yolks and whites into two separate bowls. Beat the yolks with the sugar for about 3 min. until light and fluffy (keep back 1 tsp sugar to the egg whites). Combine half the flour with the baking powder and fold it into the egg yolks.
Heat the chocolate milk and butter in a small, heavy-bottomed saucepan over a medium heat until the butter has melted. Fold it into the egg yolk mixture along with the rest of the flour and the other ingredients to make a smooth batter.
Beat the egg whites with sugar for approx. 3 min. until stiff, then carefully fold into the batter.
Heat up a frying pan nice and hot and pour out 3 portions of batter (approx. 50 ml each). Cook the pancakes for about 2 min. on each side over a medium heat. Repeat the process with the rest of the batter.
Sprinkle the pancakes with icing sugar and serve immediately with blueberries and maple syrup.
The pancakes can also be made using a crêpe or blini pan.