This recipe was comes from Katherine, the winner of our "Incredible Egg Recipe Contest". We prepared her recipe according to her directions, pictured above and below. It's super moist, not too sweet with the nutty flavour of hazelnuts. We have added our own "How To Ice Your Cake" if you're not familiar with buttercream icing. Tip: Hazelnut flour can be hard to find. You can substitute Almond Flour in the same proportion although you'll be missing the hazelnut essence.'ll have lots of icing leftover for a batch of cupcakes!

Chocolate Hazelnut Olive Oil Cake:

3/4 cup all purpose flour
3/4 cup hazelnut flour 
1-1/2 cups sugar
3/4 cup Dutch processed cocoa powder
1-1/2 tsp baking soda 
1 tsp baking powder 
1 tsp Kosher salt
1/4 cup fresh mild extra virgin olive oil 
3/4 cup buttermilk*
3/4 cup hot water or hot coffee
2 large eggs
2 tsp vanilla extract 

Nutella Buttercream Icing:
1-1/2 cups unsalted butter, softened at room temperature
3/4 cup Nutella
3 cups icing sugar, sifted 
3/4 cup Dutch processed cocoa powder, sifted 

Chocolate Hazelnut Olive Oil Cake: 
Preheat oven to 350F, grease three 6″ round baking pans with olive oil, and dust with cocoa powder. Line bottoms with parchment. Place all dry ingredients into the bowl of a stand mixer with paddle attachment, or large bowl using hand mixer on low speed. Stir to combine. In separate medium bowl mix all wet ingredients (milk, eggs, vanilla, oil). Then slowly pour and whisk in the hot water (or coffee) careful not to cook the eggs. Add wet ingredients to dry and mix for 2 to 3 minutes. You can use a hand mixer on low speed instead of a stand mixer. Be careful not to let too much air into the batter. It will be very thin. Pour evenly into prepared pans. You can use a kitchen scale to ensure the batter is evenly distributed. Bake until a cake tester comes out mostly clean, a total of 30-35mins. Let cool in baking pan for 10 minutes, then remove and place on baking rack to cool completely before icing. 
Nutella Buttercream:
Place butter in stand mixer bowl with a whisk attachment or use a hand mixer and medium bowl. Whip until creamy about 2 minutes. In another medium bowl, whisk together sugar and cocoa powder. On low speed, add sugar mixture 1 cup at a time until well blended. Scrape down sides of bowl and whisk as needed. Then add in Nutella and whip on high for approximately 5 mins. If the icing is too thick add 1 tsp milk at a time until desired consistency. 
How to ice your cake:

Once completely cooled, trim cake layers after baking to ensure a flat surface and remove any loose crumbs. Dollop a large spoon of buttercream onto bottom two layers of cake. Smooth it over to create a flat surface. No need to ice the sides yet. Then place each layer one on top of the other with the un-iced layer on top. Dollop a large spoon of buttercream onto the top layer and lightly spread over sides and top. This step is called a "crumb coat". The buttercream seals in any crumbs and smooths out the surface of the cake to take the final layer of buttercream. This layer does not need to be very thick. Use a ruler or palette knife to seal in all the crumbs. Chill in fridge for at least 30 minutes until buttercream is firm. Once chilled repeat the process with another thicker layer of icing. Chill in the fridge for an hour or until ready to serve..