Heat one-half cup sugar in a heavy skillet until it is melted and begins to smoke, stirring constantly. Add the boiling water all at once and cook, stirring until lumps have disappeared. Set aside to cool.

Cream the one and one-half cups sugar with the butter or margarine and vanilla, until light, and add the beaten egg yolks. Beat well. Sift the flour once, measure and resift with salt and baking soda and add alternately with the water to the first mixture, beating after each addition until smooth. Add the burnt sugar syrup, blend, and lastly fold in the beaten egg whites. Bake in two 9-inch greased layer cake pans, 375 degrees for about 25 minutes or until done. Cool and frost with Burnt Sugar Seven Minute Frosting.