Mozart Cake

Cake batter

 * 4 large eggs, separated
 * ½ cup granulated sugar
 * ¾ cup + 1 tablespoon flour
 * ½ cup + 1 tablespoon cornstarch
 * ½ teaspoon baking powder

Chocolate ganache filling

 * 2 cups heavy cream, divided
 * 1¼ cups (8 oz) good quality milk chocolate chips
 * 1 (4 ounces) good quality semi-sweet chocolate bar, grated, divided use
 * 2 tablespoons unsalted pistachios, finely chopped

Decorations

 * 1 (7 ounces) package marzipan paste or almond paste (you might not use all of it)
 * green food coloring paste (optional)
 * 1 tablespoon unsalted pistachios, finely chopped
 * ¾ cup heavy cream
 * 1 packet vanilla sugar (approximately ¾ tablespoon)
 * powdered sugar, to taste only if needed

Directions

 * 1) Beat egg whites until stiff but not dry, adding granulated sugar.
 * 2) Next, mix in the egg yolks one at a time, just enough to combine.
 * 3) Sift together flour, baking powder, and cornstarch; gradually and gently fold into the egg mixture to combine - be careful not to deflate the egg whites by over-mixing.
 * 4) Line a large nonstick spring-form pan with parchment paper and fill with the batter.
 * 5) Bake in a preheated oven at 350°F (175°C or gas mark 2) for 30 minutes - it will only rise up partway.
 * 6) Let cool completely.
 * 7) Meanwhile, heat ½ cup of the cream in a small pan over medium-low heat, then stir in the milk chocolate until it melts and is smooth.
 * 8) Remove pan from heat and let cool for 1 hour at room temperature.
 * 9) Finely grate the bittersweet chocolate using a microplane grater and divide into two portions.
 * 10) Beat 1½ cups of the cream until stiff peaks form.
 * 11) Stir chopped nuts and half (one portion) of the grated chocolate gently into the cooled melted chocolate mixture.
 * 12) Gently fold together the whipped cream and the cooled melted chocolate mixture until just combined.
 * 13) Remove ring from spring-form pan and carefully slice the cake into three even (very thin) layers using a large serrated knife.
 * 14) Place one cake layer on a large plate, spread with ⅓ of the chocolate ganache, then top with another cake layer, another layer of ⅓ of the ganache, followed by another cake layer.
 * 15) Spread the remaining chocolate ganache mixture all over the top and sides of the cake.
 * 16) Chill for 2 hours.
 * 17) Knead the marzipan(with enough powdered sugar to make it sweet if unsweetened) until well blended.
 * 18) Place marzipan between two sheets of wax paper and roll out into very flat circle, about the size of your spring-form pan.
 * 19) Set a plate on top of the marzipan and use the plate as a guide to cut out a perfect circle; then cut circle into 16 triangles.
 * 20) Set the marzipan triangles in a spiral around the top of the chilled cake, pressing down slightly so they stick - there should be very narrow gaps between each triangle - if desired, curl up the pointy tips decoratively first.
 * 21) Coat the sides of the cake with some the remaining grated chocolate.
 * 22) Beat the remaining ¾ cups of cream with the vanilla sugar to taste until stiff peaks form.
 * 23) Shortly before serving, garnish cake with swirls of the whipped vanilla cream, the remaining chopped nuts, and sprinkle any remaining grated chocolate on top.