Separate eggs. Beat the egg whites until stiff, adding 75 g sugar and 1 packet of vanillin sugar. Beat the egg yolks separately. Sift flour, starch and baking powder into the mixture and fold in carefully. Put the sponge cake on a greased pan lined with baking paper (approx. 38 x 32 cm) and smooth it down. Bake in the preheated oven (electric cooker: 200 °C/ gas: level 3) for about 12 minutes.
Remove the sponge cake from the oven, turn onto a tea towel sprinkled with 2 tablespoons of sugar and carefully remove the baking paper. Let the sponge cake cool down and cut into 2 rectangles (19 x 32 cm). Place the 1st plate on a rectangular tray with a high rim and enclose it with a multi-folded bar made of aluminium foil (approx. 8 cm high).
Place the nougat directly in its shell in a hot water bath (max. 50° C) and melt. Spread the nougat mixture evenly on the 1st plate, let it cool down and let it set.
Stir the espresso powder into 700 g whipped cream. Then whip until stiff, adding cream firmer and 1 teaspoon of sugar. Spread the espresso cream on the nougat layer and place the 2nd plate on top. Whip 150 g of cream until stiff, while pouring in 1 teaspoon of sugar. Spread on the 2nd plate. Chill for 2-3 hours.
Dust the cake thickly with cocoa and cut into about 15 pieces. Whip the rest of the cream until stiff, while pouring in the remaining vanillin sugar. Place in a piping bag with star-shaped spout and decorate the slices with cream tuffs and, if desired, with chocolate dessert decorations.