Beat the egg whites with powdered sugar into thick snow. Separately, whisk the egg yolks and combine them with the egg whites. Carefully add and mix with the flour. Pour the mixture into a smooth rectangular tray, covered with baking paper.
Bake the sponge cake layer in a highly heated oven until pale pink. Pour the flavored sugar syrup over the layer. For the cream, beat the eggs with the powdered sugar in a pot in a water bath on the stove. Be careful not to cook the eggs and as soon as the stirrer starts leaving a trail along the bottom, remove it from the heat.
Smear 1/2 of the cream on the layer, roll it up, remove the paper and brush the top with the remaining cream. Sprinkle the roll with crushed roasted nuts.