Chocolate Chestnut Cake

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.

Step 2

In a mixing bowl, whisk egg yolks with half the sugar (1/4 cup/50 grams) and the salt until pale and thick. Stir in the warm chocolate and set aside.

Step 3

Put egg whites in a clean bowl with cream of tartar and beat until fluffy, then add remaining 1/4 cup/50 grams sugar and beat until whites are stiff but not dry.

Step 4

Stir chestnut flour and chopped chestnuts into the chocolate batter, then fold in 1/4 of the whites to lighten mixture. Fold in remaining whites and scrape batter into an unbuttered 8-inch springform pan, smoothing top if necessary.

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.)

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.