My mom made this cake while living in the Depression. It is so good, I hope this fills your needs and your memories.
1 Preheat oven to 350 degrees (175 degrees C). Lightly grease two 9 inch layer pans.
2 Mix flour, baking soda, baking powder, cocoa, and sugar into a large bowl. Stir in mayonnaise. Gradually add water and vanilla and blend until smooth. Pour batter into prepared pans.
3 Bake at 350 degrees F (175 degrees C) for 30 minutes. Cool, remove from pans, and frost with your favorite chocolate frosting.