Mix butter, sugar, vanilla sugar and salt. Stir in the eggs one by one. Mix the flour and baking powder and stir in briefly, alternating with the milk. Let the dough swell for about 10 minutes
Preheat and grease the waffle iron. Add 1 1/2-2 tablespoons of dough per wafer and bake until golden brown. Take out and let cool on a cake rack