Separate eggs. Beat the egg whites, three tablespoons of cold water and salt until stiff. Add sugar and vanilla sugar while stirring. Stir in egg yolk. Sift flour, starch and baking powder and fold into the egg mixture. Spread the dough on a baking tray lined with baking paper and bake in a preheated oven (electric range: 200 °C/ gas: level 3) for 12-15 minutes until golden brown. Turn out the dough sheet onto a damp tea towel, remove baking paper, roll up the dough sheet.
Leave to cool. Unroll dough sheet. Spread with the nut nougat cream. Cut the dough sheet in half lengthwise. Roll up each half of the dough from the long side. Cut rolls into four pieces. Dust half of each sponge roll with icing sugar and cocoa using a dough card