Wash the oranges thoroughly, place them whole and with their skin in a small pot, cover them with a little water and let them boil covered over a low heat for about 2 hours. Lift out the oranges with a skimmer, drain and allow to cool. Cut cooled oranges in half and remove the seeds. Put the oranges in a tall cup and puree them with a blender. Mix hazelnuts, sugar, vanillin sugar, salt and baking powder. Beat the eggs with the whisk of the hand mixer until creamy. Add the orange puree and nut mixture and stir in.
Pour into a greased springform pan (22 cm Ø) sprinkled with flour and bake in a preheated oven (electric range: 175 °C/ convection oven: 150 °C/ gas: level 2) for 60-70 minutes. Remove from the oven, place on a grid, remove from the edge of the springform pan and allow to cool in the pan. Roughly chop the chocolate. Heat the cream in a small saucepan and remove from the heat. Add chocolate and coconut oil and stir until the chocolate has dissolved. Remove the cake from the mould, spread the chocolate icing over it and let it dry. Decorate the cake with chocolate rolls and orange wedges