Chocolate Torte- Bri

6 large eggs, separated

1 cup unsalted butter, cut into small pieces

9 ounces semisweet chocolate, chopped (or high quality chocolate chips)

1 cup granulated sugar

1 teaspoon pure vanilla extract

1/4 teaspoon cream of tartar

Preheat oven to 350 degrees F (177 degrees C) with rack in the center of oven Butter a 9 x 3 inch (23 x 8 cm) springform pan or spray with nonstick cooking spray. Line bottom of pan with parchment paper.

Separate the cold eggs, placing the whites and yolks in separate bowls. Cover both with plastic wrap and bring to room temperature (about 30 mins.). 

Meanwhile, melt the butter and chocolate in a heatproof bowl placed over a saucepan of simmering water. Place egg yolks and 1/2 cup sugar in the bowl of your electric mixer (or use a hand mixer). Beat on medium high speed until thick and lemon-colored, about 3-5 minutes. (Eggs should have tripled in volume, be thick and soft, and when you lift the beater the mixture falls back into the bowl in a slow ribbon.) Beat in the vanilla extract and melted chocolate mixture. 

In a clean bowl, with the whisk attachment, beat the egg whites until foamy. Add the cream of tartar and continue beating until soft peaks form. Gradually add the remaining 1/2 cup sugar and beat until stiff peaks form. Using a rubber spatula or whisk, fold a small amount of whites into the egg yolk mixture to lighten the batter. Add the remaining egg whites, folding just until incorporated. Do not over mix or batter will deflate. Pour into the pan, smoothing top. 

Bake for about 40-50 minutes or until a toothpick inserted in the center comes out with a few moist crumbs. (During baking the surface of cake will form a crust which will collapse as it cools.) Remove from oven and place on a wire rack to cool.