Panettone icing with hazelnuts

wheat flour 50.0% , sultana 25.0% , butter 12.5% , sugar 6.3% , candied orange peel 3.1% , egg yolk of fresh class a eggs 1.6% , natural yeast 0.8% , lime 0.4% , whole milk 0.2% , Emulsifier 0.1% , invert sugar syrup 0.0% , glucose-fructose syrup 0.0% , cocoa butter 0.0% , salt 0.0% , barley malt extract 0.0% , honey 0.0% , flavouring 0.0% , frosting ingredients 11.0% , white egg of fresh class a eggs 0.0% , "nocciola piemonte igp" 9.0% , rice flour 0.0% , rice starch 0.0% , sunflower oil 0.0% , flavouring 0.0%