Beat yolks with 80 g of powdered sugar until white. Add alternately egg whites broken down into snow remaining powdered sugar. Add flour, rum and vanilla. The extruded dough sticks with a length of about 4-5 cm on a buttered and dusted with flour pan. Sprinkle half of the biscuits with granulated sugar and bake in moderate oven 15 minutes. Once cool taped two by two with a thin layer of jam. frosting: condensed water bath cocoa, remaining granulated sugar and 100 ml water. Add the butter. Once cooled down in January Fill the biscuits.