Chocolate Chestnut Cake

Preparation

1. Step 1

   Heat oven to 375 degrees. Melt chocolate and butter in a bowl set over boiling water until chocolate is nearly completely melted, then remove from heat and whisk mixture until smooth.

2. Step 2

   In a mixing bowl, whisk egg yolks with half the sugar (¼ cup/50 grams) and the salt until pale and thick. Stir in the warm chocolate and set aside.

3. Step 3

   Put egg whites in a clean bowl with cream of tartar and beat until fluffy, then add remaining ¼ cup/50 grams sugar and beat until whites are stiff but not dry.

4. Step 4

   Stir chestnut flour and chopped chestnuts into the chocolate batter, then fold in ¼ of the whites to lighten mixture. Fold in remaining whites and scrape batter into an unbuttered 8-inch springform pan, smoothing top if necessary.

5. Step 5

   Bake for 25 to 30 minutes, until a toothpick inserted in the center of the cake comes out almost clean. Cool on a rack. It may sink and crack a bit on top — this is fine. Run a knife around the edge of cake to free sides and remove form. Transfer to a serving platter. (Cake may be stored, covered, at room temperature for up to 3 days.)

6. Step 6

   To serve, whip cream with 2 tablespoons sugar to a very soft consistency. Spoon over top of cake and quickly spread with a spatula. Sprinkle with chocolate curls or cocoa powder.