Chocolate Chip Cake

FOR THE CAKE:
Preheat oven to 350 degrees F. Coat a 12-cup Bundt pan with cooking spray.

Beat egg whites in a large bowl with an electric mixer on low speed until foamy. Add cream of tartar, increase speed to medium-high and beat until soft peaks form. Gradually add 1/2 cup sugar, beating until stiff but not dry (this can take up to 5 minutes).

Combine remaining 1 cup sugar, flour, baking powder, baking soda and salt in another large bowl. Beat in buttermilk, oil, vanilla and a heaping spoonful of whites with mixer on medium speed. Fold in remaining whites and chocolate chips with a whisk. Scrape batter into prepared pan, smoothing top.

Bake cake until a skewer inserted in the center comes out clean, 40 to 50 minutes. Let cool in the pan on a wire rack for 10 minutes. Invert onto rack and let cool completely.

FOR THE CHOCOLATE DRIZZLE:
Combine chocolate chips and milk in a small saucepan. Heat over low heat, stirring, until chocolate is melted and mixture is smooth. Drizzle over cooled cake. Let stand for about 45 minutes before slicing.