Ingredients
6 tablespoons unsalted butter, plus more for pan
8 ounces bittersweet or semisweet chocolate, finely chopped
6 large eggs, separating yolks and egg whites
1/2 cup granulated sugar
Confectioners’ sugar, for dusting
Sweetened whipped cream, for serving
Preparation
Preheat the oven to 275 degrees with the rack in the center. Butter the bottom and sides of a 9-inch springform pan. Set aside.
Place butter and chocolate in a large heatproof bowl and microwave in 30-second increments, stirring each time, until completely melted. Let cool slightly. Whisk in egg yolks.
In a large bowl, beat egg whites until soft peaks form. Gradually add granulated sugar, and continue beating until glossy stiff peaks form. Whisk 1/4 of the egg whites into the chocolate mixture; then gently fold in remaining egg whites.
Pour batter into the prepared pan, and smooth the top with a rubber spatula. Bake until the cake pulls away from the sides of the pan and is set in the center, 45 to 50 minutes. Cool completely on a wire rack; remove sides of pan. Serve at room temperature, dusted with confectioners’ sugar. Serve with whipped cream, if desired.
