For the coconut-ribs slice, beat butter, powdered sugar and vanilla sugar until fluffy and slowly add the yolks. Mix flour with baking powder and fold into the mixture together with the milk and cocoa. Spread the dough on a baking tray and spread jam on top.
Beat the egg whites with sugar until stiff and stir in the coconut. Spread on top of the jam. Bake the coconut ribbon slice at top and bottom heat at 175 °C for 30 minutes.