Mocha Dacquoise Cake
Martha made this incredible cake to celebrate her 10th-anniversary show.
Preheat oven to 350 degrees. Place hazelnuts on a baking sheet; toast until fragrant, about 10 minutes. Transfer nuts to a kitchen towel; rub off loosened papery skins. Let stand until cool. In the bowl of a food processor fitted with the steel blade, pulse nuts until they are the texture of coarse cornmeal; set aside.
Place a layer of chocolate dacquoise on a 12-inch cardboard cake round. Coat with a 1/2-inch-thick layer (about 2 cups) buttercream. Top with second layer. Spread ganache in an even layer over dacquoise. Top with third layer. Coat with a 1/2-inch-thick layer of buttercream. Top with fourth layer. Coat with a 1/2-inch-thick layer of buttercream. Top with final layer.
Coat the top and sides of cake with an even layer of buttercream. Press hazelnuts onto outside edge of the cake. Use remaining buttercream to decorate, as desired. Reserve any remaining buttercream for another use.