Moca Chocolate Cake

1 cup sugar
1 egg
2 Tbsp. butter
1/2 cup cocoa
1 level tsp. soda dissolved in 1 cup sour milk
1 tsp. vanilla
1 1/2 cups flour (no more!)

Make cake in usual manner being sure to cream sugar, egg and butter well. Bake off in 2 layer pans and then fill with filling.

Filling:
1/2 cup coffee, hot
1/2 cup sugar
2 Tbsp. cornstarch
2 Tbsp. cocoa, stirred in hot coffee
dollop of butter the size of an egg
1 tsp. vanilla

Frost with a 7 minute icing.