- 8 tablespoons (1 stick) unsalted butter , cut into 1-inch pieces, plus extra for pan
- All-purpose flour for pan
- 10 ounces bittersweet chocolate , coarsely chopped
- 6 large eggs , separated
- 1 cup sugar
- 1 teaspoon vanilla extract
- 1 1/2 teaspoons unflavored gelatin
- 2 cups heavy cream
- 1 tablespoon plus 2 teaspoons sugar
- 4 ounces bittersweet chocolate , coarsely chopped
- 1/2 cup heavy cream
Place chocolate in top of a double boiler over simmering water. Heat, stirring occasionally, until chocolate is almost melted. Add butter and stir until mixture is completely smooth. Remove pan from heat, discard simmering water and replace it with warm tap water. Place chocolate mixture back over water and set aside.
In a bowl with an electric mixer, beat egg yolks at medium-high speed until light and lemon colored. Gradually beat in 3/4 cup sugar until mixture becomes very thick. Switch mixer to low speed and blend in chocolate mixture and vanilla.
In a separate mixing bowl, beat egg whites until soft peaks form. Gradually beat in remaining 1/4 cup sugar until soft peaks form again. With a rubber spatula, fold 1/3 of egg whites into chocolate mixture. Fold in remaining whites until just blended. Pour batter into prepared pan; smooth top.
Bake cake 15 minutes; reduce oven temperature to 300° and bake an additional 15 minutes. Reduce temperature again to 250°; bake 30 minutes. Turn off oven, leaving door ajar and let cake stand in oven for 30 minutes. Transfer cake to a wire rack, cover pan with a damp cloth and let stand 5 minutes. Uncover and cool completely. Remove side of pan. Cake will have a crust that cracked and collapsed as temperature was reduced; gently remove top crust and discard.
To make whipped cream: Bring a small skillet filled halfway with water to a simmer. Fill a glass measuring cup with 1/4 cup cold water and sprinkle gelatin over it; let stand until gelatin softens, about 1 minute. Place measuring cup in simmering water and stir until gelatin completely dissolves. Remove from heat and cool to room temperature.
In a large mixing bowl, beat cream at medium-high speed until thick. Gradually beat in dissolved gelatin. Beat in sugar until stiff peaks form; chill.
To make chocolate glaze: Place chopped chocolate in a medium bowl. In a small saucepan, heat cream over medium heat until small bubbles form around edge of pan. Pour hot cream over chocolate and whisk until chocolate melts and forms a smooth glaze; let stand until cool enough to mound slightly with a spoon.
Meanwhile, with a long serrated knife, gently cut cake in half horizontally to make two even layers. Place one layer on a serving plate and spread a 1/2-inch layer of whipped cream over it. Gently place remaining layer on top. Cover top and sides of cake with remaining whipped cream, making it as smooth as possible. Freeze cake for 30 minutes.
Remove cake from freezer and pour chocolate glaze over top. Smooth with a spatula, allowing excess glaze to drip down sides of cake. Refrigerate cake at least 1 hour before eating. Makes 20 servings.