Cream together the sugar, vanilla sugar and butter. Add the egg and mix until completely incorporated.
Add the flour and mix to a firm dough. Wrap the dough in foil and refrigerate for at least an hour.
On a floured work surface, roll out the dough to about 5 mm thick. Don't use too much flour: since the recipe already contains a lot of flour, the cookies will taste too "floury".
Cut out the cookies with a cookie cutter of your choice. Place the cookies on a baking sheet and bake at 180°C/350℉ (conventional oven) for about 10-12 minutes. Small cookies will bake a little faster, so it is best to bake the same size cookies per sheet.
Remove the cookies from the oven when the edges are golden brown. The cookies will still be a little soft when they come out of the oven, so let them cool a bit before placing them on a wire rack.
When the cookies are completely cool, you can decorate them with royal icing or melted chocolate.
How to store
Undecorated cookies are best stored in an airtight container, where they will keep for 4 to 6 weeks. Learn more about storing decorated cookies.