Ferrero Rocher Cake

Ingredients

• 3/4 cup all purpose flour
• 3/4 cup hazelnut flour
• 1 1/2 cups granulated sugar
• 3/4 cup Dutch-processed cocoa powder sifted
• 1 1/2 teaspoons baking soda
• 1 teaspoon baking powder
• 1 teaspoon salt
• 1/4 cup vegetable oil
• 3/4 cup buttermilk
• 3/4 cup hot water
• 2 large eggs
• 2 teaspoons vanilla
• 1 1/2 cups unsalted butter room temperature
• 3/4 cup Nutella
• 3 cups powdered sugar sifted
• 3/4 cup Dutch-processed cocoa powder sifted
• 2 large egg whites
• 5 tablespoons granulated sugar
• 1 pinch salt
• 1 pinch cream of tartar
• 1/2 cup chopped hazelnuts toasted skinned
• 1 1/2 tablespoons Dutch-processed cocoa powder sifted