Mix the butter with the egg and sugar until frothy. Add the ground walnuts. Mix flour with baking powder and gradually add. Put the dough in a cool place, preferably overnight.
Dust the work surface with flour and roll out the dough to a thickness of 2-3 mm. The cookies as needed, e.g., with the smallest and medium-sized shape of the terrace molds, cut out and place on a baking sheet lined with baking paper.
Bake the cookies at about 175 ° C for about 10 minutes.
After the biscuits have cooled down, glue 2 biscuits with apricot jam together.
Mix the powdered sugar with the brandy. Brush the double biscuits with it and place half a walnut on top.