Sort the blueberries, wash and drain. Defrost frozen berries. Cream butter, sugar, vanilla sugar and 1 pinch of salt. Stir in the eggs one by one.
Mix flour and baking powder and stir into the dough alternating with the cream. Fold in blueberries.
Preheat the waffle iron and spread a thin layer of oil on it. Place approx. 1 1⁄2 tbsp. of dough in the middle of each waffle iron and bake according to the instructions for use until golden yellow. Bake about 7 more waffles from the remaining dough.
Dust with icing sugar. A strawberry cream is also delicious with it.