Coarsely chop 250 g whole milk couverture. Melt fat, coffee and chopped couverture in a hot water bath. Leave to cool slightly. Coarsely chop the pistachios and walnuts. Put some nuts and pistachios aside for decorating.
Beat the eggs, 340 g sugar, vanillin sugar, orange baking powder and salt with the whisk of the hand mixer for about 10 minutes until frothy. Add melted fat-chocolate mixture to the sugar cream and stir in.
Mix flour and baking powder, sieve over it and stir in briefly. Fold in nuts and pistachios. Pour the dough into a greased and flour-polluted ring cake tin (2 1/2 litres capacity) and smooth it down.
Bake in the preheated oven (electric cooker 175 °C/ convection oven: 150 °C/ gas: level 2) for 45-50 minutes. After approx. 35 minutes, cover with aluminium foil if necessary. Let the ring cake rest in the pan for about 5 minutes, then turn out onto a cake rack and let it cool down completely.
For the icing, roughly chop 200 g of whole milk couverture and melt in a hot water bath. Cover the cake with it. Caramelise 30 g sugar in a pan. Turn the nuts in it, spread on a piece of oiled aluminium foil and let it get firm.
Gugelhupf with caramel nuts decorate.