Sift the flour onto the work surface. Add sugar, vanilla sugar, egg yolk, Citroback and butter and make a kneading dough. Put in a cool place.
Roll out the dough, cut out round serrated cookies and rings of the same size. Place the biscuits on a prepared baking sheet, the rings on another sheet, as the baking times are different.
Baking time at 180 degrees approx. 10-15 minutes.
Mix the apricot jam with the rum and brush the cookies with it. Dust the rings with powdered sugar and place on the cookies.