Ingredients 1 cup pecan halves1/4 cup plus 2 tablespoons sifted unsweetened cocoa1 teaspoon ground cinnamon7 tablespoons butter , melted5 eggs , separated1 1/4 cups sugarSalt3 tablespoons cake flour , sifted
Preheat the oven to 350°. Butter an 8-inch square baking pan. Dust the pan with flour and tap out excess.
Place half the pecans on a baking sheet and toast in the oven for 5 to 10 minutes, shaking the pan once or twice, until the nuts are fragrant. Let the nuts cool slightly. (Leave the oven on.)
In the bowl of a food processor, process the toasted nuts until finely ground, about 45 seconds. Set aside.
Whisk the cocoa and cinnamon into the melted butter. Set aside.
In the bowl of an electric mixer fitted with a whisk attachment, beat the egg yolks with 1/2-cup sugar at medium-high speed until thickened and pale, about 3 minutes. At low speed, mix in the cocoa mixture and ground pecans.
In a clean mixer bowl, using a clean whisk attachment, beat the egg whites with the salt until foamy. Gradually add the remaining 3/4-cup sugar and beat until stiff but not dry. Gently fold the whites into the egg yolk mixture in three additions, alternating with the cake flour in two additions. Scrape the batter into the prepared pan and sprinkle with the remaining pecans.
Bake for 45 to 50 minutes, until the cake springs back when lightly touched and a toothpick inserted in the center comes out with a few moist crumbs clinging to it. Cool the cake in the pan on a wire rack for 15 minutes. Unmold the cake and cool completely on the rack.
Cut the cake into squares to serve. Store, well wrapped, in the refrigerator for up to a week.