Preheat your oven 180°C. In a bake tray place a non-stick paper and place the hazelnuts. Bake for 10’ Let them cool for a while and rub the nuts with your palms in order to remove the peel. Add in in a blender and ground coarsely.
In a bowl we sift the flour, cocoa, sugar vanilla and baking soda. Add the salt and mix all together well.
In a separate bowl we add the oil and the sugar.  Mix well with the confectionery wire until fluffy. Add the vinegar.  And finally add the water and them the dry ingredient small portions at a time. Keep some flour for the top part of the cake. Sprinkle with the flour and add the hazelnuts this technic will not allow the hazelnuts to end up in the bottom of the cake. Butter a round cake tray with a hole in the middle. Add the mixture and bake in preheated oven for 40’ Let it cool, remove from the tray and decorate it with some extra hazelnuts on top.