Butter the bottom and sides of an 8” round cake pan. Line the bottom with parchment paper and butter the parchment paper. Coat the sides and bottom with flour and tap out the excess. (My pan of choice is USA Pan.)
Preheat your oven 350 degrees Fahrenheit.
In the bowl of a stand mixer or in a large bowl using a hand mixer, cream together the butter and brown sugar for 1-2 minutes on medium speed, until the mixture is light in color.
Add the egg and beat on medium speed until combined.
Whisk together the buttermilk, oil and vanilla extract.
Whisk together the flour, cocoa powder, baking soda, baking powder and salt. Add the zucchini and toss to coat.
Add half of the flour mixture and beat on low just until you no longer see any flour.
Add the liquid ingredients and continue to mix on low until combine.
Add the remaining flour and beat on low just until you no longer see and flour.
Using a spatula scrape the bottom and sides of the bowl to make sure all the ingredients are incorporated.
Place 1/2 the batter in the pan and using an offset spatula smooth to an even layer.
Warm the chocolate hazelnut spread in the microwave for 15-20 seconds so that it has a consistency that you can drizzle.
Drizzle the spread over the first layer of batter.
Top with the remaining batter and spread to an even layer.
Sprinkle the top with the chopped hazelnuts and 2 teaspoons of sugar.
Bake for 25-28 minutes or until the top springs bake when gently pressed.
Place the pan on a rack and allow the cake to cool completely.
Invert the cake onto a wire rack. Top with a plate and invert again.
You can drizzle the top with some chocolate hazelnut spread or leave it plain.