Cream fat, sugar, vanillin sugar and salt. Stir in eggs bit by bit. Mix flour, starch and baking powder and stir into the fat-egg mixture. Add orange fruit, orange juice and orange liqueur.
Put the mixture on a baking tray lined with baking paper and smooth it down. Bake in the preheated oven (electric oven: 200 °C/ gas: level 3) for approx. 20 minutes. After 10 minutes, cover with parchment paper if necessary.
Let it cool down. Coarsely chop the pistachios. Heat up orange marmalade while stirring. Spread the cake with it. Sprinkle with pistachios. Cut the cake into rhombs and decorate with candied orange slices as desired.
Results in about 24 pieces.