Melt the butter, brown it lightly and let it cool down. The butter needs to be a little warm. Stir until creamy until liquid. Gradually add the sugar, salt and vanilla sugar. Add the flour by tablespoon.
Shape the dough into rolls immediately (can be a little difficult, possibly use cling film to help). Chill for 12-14 hours.
Then cut the dough into slices (may crumble a bit) and place on a non-greased tray. Bake the heather sand for 20-25 minutes at 170 ° C.