Flourless Chocolate Cake

Preheat the oven to 275 degrees with the rack in the center. Butter the bottom and sides of a 9-inch spring form pan.

Place butter and chocolate in a large heatproof bowl and microwave in 30-second increments, stirring each time, until completely melted.

Add salt.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 or ice cream, if desired