Wash the oranges, rub dry, rub off the peel and put aside. Peel oranges so that the white skin is completely removed. Remove the fillets between the parting skins and cut them in half.
Drain the orange pieces on kitchen paper and, except for 2 tablespoons for decoration, dust with 3 tablespoons of flour. Beat the fat and sugar until creamy with the whisks of the hand mixer. Add salt, vanilla sugar and orange zest, except for 1 tablespoon for decoration.
Stir in the eggs one by one. Add orange juice. Mix 175 g flour, starch and baking powder and stir in. Carefully fold prepared orange pieces into the dough. Pour into a greased and floured ring cake tin (1.7 litres capacity).
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 45 minutes. Then turn out onto a cake rack and let it cool down. Dust with icing sugar. Whip the cream until stiff, fill into a piping bag with star-shaped spout.
Serve buffers decorated with cream tuffs, orange fillets and zest.