For the dough, mix flour, 50 g sugar, vanillin sugar, yeast and salt, add eggs and set aside. Melt 60 g butter in a small pot at low heat. Add milk and 50 ml water and take the pot off the heat
Pour the milk-butter mixture into the flour-sugar mixture and knead into a smooth dough with the dough hooks of the hand mixer. Cover the dough and let it rise for about 1 hour until it has doubled in size
Wash the oranges in hot water, grate them dry and cut the peel into thin strips with a pestle ripper. Coarsely chop the zests and sultanas
Knead the yeast dough briefly and roll out on a floured work surface (approx. 50 x 50 cm). Spread thinly with 80 g butter. Cut into 6 strips of equal width (approx. 8 cm) with a rolling knife. Spread the orange and sultana mixture evenly on top. Mix 6 tbsp. sugar and cinnamon and spread evenly on the dough. Cut the dough strips crosswise into 5 pieces (approx. 8 x 10 cm)
Place a greased box form (30 cm long; 1 3/4 litre capacity) on its edge. Fold the dough pieces together, pull them slightly in length and width, and layer them one after the other in the box mould, so that the openings alternately point to the front or back. If the crate mould is not completely full at the end, tilt the crate mould and distribute the dough flaps so that the crate mould is filled. Cover and leave to rise again for about 15 minutes
Bake in the preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 30 minutes. Take the cake out of the oven and let it rest in the mould for about 10 minutes. Turn out of the mould. For the icing, stir icing sugar and 2 tbsp. water until smooth and spread on the cake. Let the cake cool down
waiting time approx. 2 hours