Sour-Cream Chocolate Cake

� cup soft butter
1 cup sugar
1 egg yolk -- beaten
� cup sour cream
1 teaspoon baking soda
� teaspoon salt
1� cups flour
� teaspoon baking powder
1 teaspoon vanilla
3 tablespoons cocoa
� cup boiling water
1 egg white -- beaten stiff
1 tablespoon cocoa
1 tablespoon cornstarch
2/3 cup sugar
� cup cold water
1 tablespoon butter
� cup hot water
1 teaspoon vanilla
� cup granulated sugar
1/3 cup brown sugar
3 tablespoons hot water
2 egg whites -- beaten frothy

Cream butter and sugar. Stir in egg yolk. Stir the soda into the sour cream. Sift the dry ingredients together twice. Add all ingredients to the butter-sugar mixture in the order given.

Bake in 2 buttered and lightly floured layer-cake tins about 20 to 25 minutes in a preheated 350� oven.

When cool, spread top of one layer with the filling: Mix filling ingredients in order given and cook 20 minutes, stirring often so mixture will not scorch.

Center plain layer over filled layer and frost top and sides with frosting:

Boil sugars and water until they spin a thread. Pour slowly over the beaten egg whites. Frost the cake.

Melt 2 ounces (2 squares) of unsweetened chocolate over hot water. Pour over cake and let drip down the sides.