A sponge cake is a cake made with eggs, flour, sugar, and butter or oil, without using a raising agent. The cake is believed to have originated in Europe in the early 18th century.
Sift the flour 4 times.
Beat yolks of eggs until light and thick.
Graduallyadd 1/2 of the sugar, the lemon rind and vanilla.
Beat the whites untilstiff and add the cream of tartar and the remaining sugar.
Combine the eggmixtures.
Add salt to flour and fold into the egg mixture lightly.
Pourinto an ungreased pan with center tube.
Bake at 325-F for 1 hour.