Chop the beetroot finely, mash it. Chop 100 g nuts. Cream fat, 150 g sugar, vanillin sugar and salt with the whisk of the hand mixer. Stir in eggs one after the other. Mix flour, baking powder and cocoa, alternately stir in beetroot.
Fold in chopped nuts.
Pour into a greased, flour-sprinkled box form (11 x 25 cm; approx. 1.25 l capacity) and smooth it down. Bake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: see manufacturer) for approx. 45 minutes.
Remove and let it cool down on a cake rack.
Meanwhile melt 25 g sugar in a small pan, caramelise the remaining nuts in it while stirring. Spread the nuts on baking paper and let them cool down.
Carefully remove the cake from the mould and place it on a cake rack. Mix icing sugar with 6 tbsp. water. Spread the icing evenly over the cake. Spread caramel nuts on top. Let the icing dry for about 30 minutes.
Cut the cake into slices. Whipped cream tastes good with it.