Mix the flour, sugar, vanilla sugar and salt well in a bowl. Then melt the butter in a saucepan and pour in the milk and let it warm up slightly. Crumble in the yeast and dissolve. Mix the milk mixture with the 2 eggs and the flour mixture and let the dough rise in a warm place for about half an hour.
Finally, bake the dough in portions in the waffle iron. Best served warm and dusted with powdered sugar.
Be careful, the milk must not be too warm, it should be about lukewarm.