Caramelise 75 g sugar and maple syrup in a pan. Add the walnuts and turn until the nuts are coated with caramel. Put the nuts on a piece of baking paper and let them cool down. Do not chop the nuts too small. Cream fat, vanilla sugar, salt and 200 g sugar with the whisk of the hand mixer. Stir in the eggs one by one. Mix flour and baking powder and stir in alternately with the milk.
Fill 1/4 of the dough into a greased, flour-spread box form (30 cm long, 2 3/4 litres capacity). Add 2/3 of the chopped nuts to the remaining dough and fill into the tin. Bake the cake in a preheated oven (electric cooker: 175 °C/ convection oven: 150 °C/ gas: level 2) for approx. 60 minutes (stick test). Remove the cake from the oven, let it cool down for approx. 15 minutes and turn out of the tin. Let them cool down on a cake rack. Melt the icing in a warm water bath, then spread over the cake. Sprinkle with remaining caramel nuts and chill for approx. 30 minutes
waiting time approx. 1 1/2 hours