12 ounces bittersweet chocolate, chopped (you can also use 12 ounces of Ghirardelli double chocolate chips)
3/4 cup unsalted butter, cut into pieces
6 large eggs, separated
12 tablespoons sugar
2 teaspoon vanilla extract
- Stir chocolate and butter in a medium saucepan, over low heat. Stir until chocolate is melted. Set aside.
- Preheat oven to 350F.
- Prepare a 9-inch diameter springform pan. Butter the bottom of the pan. Line the pan with parchment or wax paper. Butter the paper. Wrap the outside of the pan with foil.
- Separate the eggs.
- With an electric mixer, beat the egg yolks with 6 tablespoons of sugar. Beat until the yolks are light yellow and thick, about 5 minutes.
- Slowly add the yolks to the chocolate mixture.
- Using clean beaters and bowl, beat the egg whites, until a soft peaks form Add 6 tablespoons of sugar to the egg whites, continue to beat until firm peaks form.
- Fold egg white mixture into chocolate mixture. Pour batter into the prepared pan.
- Bake cake for about 50 minutes, or until a cake tester comes out clean with only a few moist crumbs. The cake will be puffed and cracked. Cool cake in the pan on a rack. The cake will fall as it cools.
- When the cake is completely cooled, gently press down the top to make an even cake.
- Loosen the pan sides by cutting around the sides with a knife. Invert the cake onto a plate or a cookie sheet.