Cream butter, icing sugar, vanillin sugar and 1 pinch of salt. Stir in the egg. Alternately stir in flour and milk briefly. Pour into a piping bag with a large star-shaped spout. Spray curls and S-forms onto baking trays lined with baking paper
Sprinkle some of the biscuits with chopped pistachios and press lightly. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for approx. 15 minutes. Let them cool down