• Preheat oven to 350 degrees. Grease and flour a 10-inch tube pan. Knock out excess flour. In a large bowl, pour the boiling water over the
• chocolate and butter; let stand until melted. Stir in the vanilla and sugar, then whisk in egg yolks one at a time, blending well aer each addition.
• Mix baking soda, and sour cream together and add to chocolate mixture. Si together flour and baking powder; add to batter, mixing thoroughly.
• In a separate bowl, beat egg whites until stiff but not dry. Stir a quarter of the egg whites into the batter. Scoop remaining egg whites on top of
• batter and gently fold together. Pour the batter into prepared pan. Set in the middle rack of oven and bake 40-50 minutes, or until the edges have
• pulled away from the sides of the pan and a cake tester inserted into the center comes out clean. Cool cake in pan for 10 minutes; unmold and cool completely before frosting.

Chocolate Frosting

• Place all ingredients in a heavy saucepan over low heat and whisk until smooth. Cool slightly;
• add more sugar if necessary to achieve a spreading consistency. Spread on cake while frosting is still warm.