Boil up the cream. Dice nougat. Pull cream off the stove. Melt the nougat in it while stirring. Let it cool down. Put it in a cool place overnight.
Line a baking tray (approx. 35 x 40 cm) with baking paper. Separate the eggs. Beat the egg white and salt until stiff, adding sugar and vanillin sugar. Beat the egg yolks separately into the mixture. Sift flour, starch and baking powder into it and fold in. Spread on the baking tray. Bake in the preheated oven (electric range: 175 °C/ convection oven: 150 °C/gas: level 2) for 12-15 minutes. Turn onto a damp tea towel and remove the paper immediately. Allow to cool down
Whip the nougat cream until stiff, while pouring in the cream firming agent. Coarsely grate the marzipan. Stir orange peel and orange juice until smooth with a hand mixer. Halve the sponge cake 1x crosswise to make 2 smaller plates. Spread the 1st plate with marzipan. Spread nougat cream on top. Place the 2nd plate on top. Chill for about 2 hours.
Coarsely chop the couverture, melt separately in a hot water bath. Cover the cake with dark chocolate coating. Spread the white couverture with a teaspoon as a blob, spread it marble-like with the back of the spoon. Leave to dry. Decorate with orange slices, orange peel and chocolate decoration