MAKES ONE 9" CAKE
This dense cake, inspired by a Julia Child recipe, has been served daily at Zuni Café since it was introduced, in 1982.
1 1/2 tsp. butter
5 whole eggs
2 egg yolks
6 tbsp. sugar
10 oz. bittersweet chocolate, chopped
6 tbsp. strong brewed coffee
3/4 cup heavy cream
1. Preheat oven to 350°. Grease a 9" cake pan with butter, line bottom and sides of pan with buttered parchment paper, and set pan aside.
2. Combine whole eggs, egg yolks, and sugar in a large heatproof bowl, set bowl over a pot of very gently simmering water, and stir until mixture is room temperature. Remove bowl from heat and beat mixture with an electric mixer on medium speed until quadrupled in volume, 15–20 minutes. Melt chocolate and coffee together in a medium heatproof bowl set over the pot of simmering water, stirring often. Remove bowl from heat. Whip cream in a medium bowl until soft peaks form.
3. Fold one-quarter of the egg mixture into the melted chocolate, then fold chocolate mixture and whipped cream into remaining egg mixture. Pour batter into prepared pan and set pan in a roasting pan. Pour hot water into roasting pan to a depth of 1" and transfer to oven. Bake cake until a toothpick inserted in center of cake comes out clean, 1 hour. Turn off oven, leave oven door ajar, and let cake rest for 30 minutes. Remove cake from oven in its water bath and let rest for 30 minutes more. Remove cake from oven water bath, invert onto a plate, and peel off parchment. Serve warm or at room temperature with whipped cream, if you like.