Quickly mix all ingredients in a bowl or on a countertop to make shortbread. Let rest in a cool place for a short time.
On a floured work surface or between two baking mats, roll out the dough to the thickness of the back of a knife, cut out any cookie shapes and place on a prepared baking sheet.
Bake in the preheated oven at 165 – 175 °C for about 10 minutes until light brown on sight.
When cooled, spread one cookie on each side with currant jam and place a second one on top.
If desired, decorate with chocolate icing or dip halfway through and allow to dry.