Preheat the oven to 180ºC (360ºF). Lightly grease a 25-cm (10-in) round cake pan and line the base with baking paper.
Blend chocolate and 2 tablespoons of nuts in a blender until become powder. In a separate bowl, beat the sugar, butter, vanilla, cinnamon and eggs together until thick and pale.
Sift in the flour and baking powder. Add the remaining nuts and milk and stir to combine. Add the grated potato and chocolate with nuts powder to the mixture. Mix well until well incorporated.
Pour into the prepared pan and bake for 60 minutes, until golden brown. Leave the cake to cool in the pan for 20 minutes before turning out into a rack to cool completely.
Mix topping ingredients well and spread evenly on the cake. Dust generously with grated nuts.
Serve, share and enjoy!
