Chocolate Marble Loaf Cake

This was a great 1940s cake to bake..

From Better Homes and Gardens Magazine October 1940 it was a great success with the family. Marble cake is the best of both worlds—tender yellow cake with distinct chocolate swirls, offering a delightful combination of flavors and textures.

This version uses chocolate bar squares not cocoa powder and incorporates stiff-beaten egg whites for a lighter texture.
The only change I made was to put the icing on top of the cake and not all over like the recipe states

1/3 cup shortening

1 cup sugar

1 teaspoon vanilla

2 cups cake flour

1/4 teaspoon salt

2 teaspoons baking powder

2/3 cup milk

3 stiff-beaten egg whites

1 1-ounce square un-sweetened chocolate, melted

2 tablespoons hot water

¼ teaspoon soda

• Cream shortening and sugar; add vanilla. 
• Add sifted dry ingredients alternately with milk. 
• Fold in egg whites. 
• Separate mixture evenly into two bowls
• Combine chocolate, water, and soda
• Add to one half the batter. 
• Alternate light and dark batter by spoonfuls into greased 4- by 8-inch loaf pan. 
• Bake in moderate oven (350°) 1 hour.