Torta Gianduia (Italian Chocolate – Hazelnut Cake)

Method

• Adjust the oven rack to the middle position and heat the oven to 350F / 180C. Line the bottom of a 9-inch springform pan with parchment paper and grease the pan sides only.
• Melt the chocolate in a water bath, stirring occasionally, until melted. Let cool completely. Place hazelnuts, 1/4 of the sugar, flour and salt in a food processor until hazelnuts are finely ground; set aside.
• Using a mixer, fitted with a whisk attachment, whip egg whites and cream of tartar on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and whip until stiff peaks form, 3 to 4 minutes. Set aside. Re-fit the mixer with a paddle attachment. In a second bowl, combine butter and the remaining sugar and beat on medium-high speed until pale and fluffy, about 3 minutes. Add egg yolks, one at a time, and beat until combined. Reduce speed to low, add cooled chocolate and mix until just combined. Add hazelnut mixture and mix until just combined, scraping down the bowl as needed.
• Using a rubber spatula, stir one-third of the egg white mixture into the batter. Gently fold the remaining egg white mixture into the batter until no white streaks remain. Transfer the batter to the prepared pan and smooth the top with the rubber spatula. Gently tap the pan on the counter to release air bubbles. Bake until a toothpick inserted halfway between the center and outer rim of the cake comes out clean, 45 to 50 minutes. The center of the cake should still be moist.
• Allow the cake to cool completely in the pan on a wire rack, for about 3 hours. Run a thin knife around the edge of the pan to loosen the cake, then remove the sides of the springform. Invert the cake onto a sheet of parchment paper. Peel off the discard the parchment paper baked onto the cake. Turn the cake right side up onto a platter. Discard the parchment. Dust the cake with confectioners’ sugar before serving.