Chocolate Walnut Cake

1. Preheat oven to 375 degrees F. Lightly oil and flour a 9-inch springform pan, tapping out any excess flour.

2. Crack 2 eggs into a large bowl. Separate 2 more eggs, placing the whites in a second large bowl and adding the yolks to the bowl with the whole eggs. Separate the remaining 4 eggs, adding the whites to the other whites (reserve the 4 yolks for another use.) You should have 6 whites in one bowl, 2 whole eggs plus 2 yolks in the other bowl.

3. Beat the egg whites with an electric mixer at high speed until foamy. Add 1/3 cup granulated sugar and continue beating until soft peaks form. Set aside.

4. Clean and dry the beaters. Add brown sugar and the remaining 2/3 cup granulated sugar to the eggs and yolks and beat with the mixer at medium speed until thick and light in color, about 3 minutes. Scrape down the sides of the bowl with a rubber spatula; beat in the toasted ground nuts and vanilla until combined. Beat in flour, cocoa powder, salt and cinnamon just until combined, scraping down the sides as needed. Fold in 1 cup of the beaten whites with a rubber spatula until smooth, then fold in the remaining whites with very gentle arcs, just until incorporated (some white streaks may still be visible). Gently pour the batter into the prepared pan.

5. Place the pan in the oven and reduce heat to 325 degrees F. Bake the cake until set, puffed and spongy but nonetheless firm, 40 to 45 minutes. Transfer to a wire rack and let cool completely, about 2 hours. As it cools, the cake will shrink away from the sides of the pan.

6. Remove the pan's side. Release the cake from the pan's bottom using a long, thin, metal spatula and carefully transfer it to a serving plate. Slice the cake horizontally into two layers with a long, thin knife. Gently lift off the top. Spread the marmalade (or jam) over the bottom layer and replace the top. Do not press down. Sprinkle with confectioners' sugar just before serving.

Tips:
Tip: To toast and grind walnuts, spread them on a baking sheet and bake at 350 degrees F, stirring once, until fragrant, 7 to 9 minutes. Let the nuts cool on a plate then grind into a coarse meal in a food processor or blender.

MAKE AHEAD TIP: Equipment: 9-inch springform pan