1 c. boiling water
3 oz. unsweetened chocolate
8 tbsp. sweet butter
1 tsp. vanilla
2 c. granulated sugar
2 eggs, separated
1 tsp. baking soda
1/2 c. sour cream
2 c. less 2 tbsp. sifted all-purpose flour
1 tsp. baking powder

Preheat oven to 350 degrees. Grease and flour 10-inch tube pan. Pour boiling water over chocolate and butter; let stand until melted. Stir in vanilla and sugar, then whisk in egg yolks one at a time.

Mix baking soda and sour cream and whisk into chocolate mixture. Sift flour and baking powder together and add to batter, mixing thoroughly. Beat egg whites until stiff. Stir a quarter of the egg whites thoroughly into batter; scoop remaining on top of batter and gently fold in.

Pour batter into prepared pan. Bake 40-50 minutes until cake tester inserted into center comes out clean. Cool 10 minutes and unmold. Cool completely before frosting.

FROSTING:

2 tbsp. butter
3/4 c. semi-sweet chocolate chips
6 tbsp. heavy cream
1 tsp. vanilla
1 1/4 c. sifted confectioners sugar

Place all ingredients in heavy saucepan over low heat and whisk until smooth. Cool slightly; add more sugar if necessary. Chill.