Yield: One 6 inch 3-layer cake or
One 9 inch 2-layer cake
Prep Time: 1.5 hours
Bake Time: 40 minutes

Ingredients

Dark Chocolate Cake
2 cups               flour
½ cup                cocoa powder
1 tsp                  baking soda
1 tsp                  baking powder
½ cup                ground hazelnuts
1 ½ cups           granulated sugar
1 tsp                  salt
6 oz                   bittersweet chocolate, melted
1 cup                 butter, melted
1 cup                 whole milk
¾ cup                buttermilk
4                         large eggs

Hazelnut Buttercream
1 cup                 butter, room temp
2 cups               powdered sugar
2 tbsp                cocoa powder
1 tsp                  hazelnut extract
½ tsp                 salt
2 tbsp                heavy cream

Candied Hazelnuts
1 cup                 granulated sugar
¼ cup                water
roasted whole hazelnuts, skinned

Kitchen Notes: I like to bake and freeze my cake layers the night before I actually need them. They're much easier to frost when frozen.

Instructions

Dark Chocolate Cake

1. Preheat oven to 325 degrees Fahrenheit. Line cake pan bottoms with parchment paper and butter sides.
2. Sift together the flour, cocoa powder, baking soda, and baking powder in the bowl of a stand mixer. Add the ground hazelnuts, granulated sugar, and salt, and mix at low speed with the paddle attachment to combine. 
3. Add bittersweet chocolate, butter, milk, and buttermilk to dry ingredients, and mix at medium speed until just combined. 
4. Add one egg at a time, mixing until fully incorporated before adding the next. Mix batter just until smooth, being careful not to over mix.
5. Split batter evenly and pour into cake pans.
6. Bake for approximately 40 minutes, until the tops of the cake layers are springy and a skewer inserted into the center comes out clean. 
7. Let the cakes cool completely in the pans before removing.

Hazelnut Buttercream

1. Place butter in the bowl of a stand mixer and beat using the paddle attachment at medium high speed until smooth.
2. Add powdered sugar, cocoa powder, hazelnut extract, and salt, and mix at low speed until fully incorporated. Then beat at medium speed for about two minutes. 
3. Add cream as necessary to obtain a smooth consistency. 

Candied Hazelnuts

1. Place a pastry slab or cutting board on the edge of a counter and line the floor below with parchment paper.
2. Insert the tip of long wooden skewer into each hazelnut.
3. Combine sugar and water in a small saucepan, stirring until smooth.
4. Cook over medium high heat -- make certain not to stir while heating to avoid forming crystals.
5. Continue to cook until the caramel acquires a light amber color. Remove from heat immediately, as the caramel will continue to cook for a few moments after. Allow caramel to cool until it just starts to thicken. 
6. Dip each hazelnut in the caramel and place the other end of the skewer under the slab or board. If the caramel was the correct consistency, a strand should form and fall to the floor. If the caramel becomes too thick as you are working, you can place it back on the stove on low heat until it reaches the correct consistency again. 
7. Allow the caramel strands to harden, cut to even desired length, and carefully remove skewers from hazelnuts. 

Credits: The recipe for these spectacular candied hazelnuts is courtesy of Olivia at Liv for Cake. Head over to her website for a full tutorial on how to make them.