Yield
Serves 8

Hazelnuts from Piedmont are truly something special with their fine flavor and extremely crisp texture. Although they're beloved in many dishes, the flavor combination of hazelnuts and chocolate, called gianduia, is a Piedmontese favorite. Sometimes gianduia refers to a fudge-like confection that’s sold in bar form, sometimes to a spread (think: Nutella), and sometimes to the popular gelato flavor. But it’s also a favorite in cakes, and just about any cake from the region that features chocolate and hazelnuts might be called torta gianduia—some are dressed-up and multilayered, while others are low, lush, and glazed. We love the classic rustic version with a crackly, crisp top and a moist, dense interior that’s something like a nutty flourless chocolate cake. The taste and texture are dependent on a delicate balance of whipped eggs (for structure and lift), butter, sugar, bittersweet chocolate, and ground hazelnuts. The quantity of nuts was of particular import. We started with 6 ounces of chocolate and 1 cup of nuts, but found the chocolate overpowered the more delicate hazelnut flavor and the texture was actually too moist and fudgy. One and a third cups of nuts was better, but we still felt the cake could be lighter; we found that replacing a small amount of the nuts with regular flour—2 tablespoons—provided a rich, melt-in-the-mouth cake that wasn’t overly weighty. All this super-rich cake needed to finish was a dusting of powdered sugar for rustic charm. Serve with lightly sweetened whipped cream.

Ingredients

  • 6 ounces bittersweet chocolate, chopped
  • 1 1/3 cups hazelnuts, toasted and skinned
  • 1 cup (7 ounces) granulated sugar
  • 2 tablespoons all-purpose flour 
  • 1/4 teaspoon salt 
  • 5 large eggs, separated, plus 1 large yolk
  • Pinch cream of tartar 
  • 8 tablespoons unsalted butter, softened 
  • Confectioners’ sugar

Tasting Italy: A Culinary JourneyTasting Italy: A Culinary Journey
by America's Test Kitchen and National Geographic

Directions

1 Adjust oven rack to middle position and heat oven to 350 degrees. Grease 9-inch springform pan, line with parchment, then grease pan sides only.

2 Microwave chocolate in bowl at 50 percent power, stirring occasionally, until melted, 2 to 4 minutes; let cool completely. Pulse hazelnuts, 1⁄4 cup granulated sugar, flour, and salt in food processor until finely ground, about 10 pulses; set aside.

3 Using stand mixer fitted with 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; transfer to large bowl. 

4 Return now-empty bowl to mixer and beat butter and remaining 3/4 cup granulated sugar 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 sides of bowl as needed.

5 Using rubber spatula, stir one-third of whites into batter. Gently fold remaining whites into batter until no white streaks remain. Transfer batter to prepared pan, smooth top, and gently tap pan on counter to release air bubbles. Bake until toothpick inserted halfway between center and outer rim of cake comes out clean, 45 to 50 minutes. (Center of cake will still be moist.)

6 Let cake cool completely in pan on wire rack, about 3 hours. (Cooled cake can be wrapped in plastic wrap and refrigerated for up to 4 days; let sit at room temperature for 30 minutes before serving.) Run paring knife around edge of cake to loosen, then remove sides of pan. Invert cake onto sheet of parchment paper. Peel off and discard parchment baked onto cake. Turn cake right side up onto serving dish. Dust with confectioners' sugar and serve.

Excerpted from Tasting Italy: A Culinary Journey by America's Test Kitchen, Eugenia Bone and Julia Della Croce. Copyright 2018 National Geographic.