Preheat oven to 350 degrees.
Sift together the dry ingredients.
In a separate bowl, briskly whisk together the eggs and light brown sugar until no lumps remain.
Blend in the vanilla and mayo until well combined.
Mix in the dry ingredients and hot water alternately. The batter will appear a bit thin.
For cupcakes, place 1 1/2 large scoops of batter in paper cupcake liners. Bake for 15 minutes. Cool for about 5 minutes before removing from pan.
For 2-8" cakes, place batter in pans lined with parchment paper bottoms and sprayed with non-stick baking spray like Baker's Joy. Bake for 30-35 minutes or until toothpick comes out clean. Allow to cool for about 5 minutes before removing from pans. Frost when completely cooled.
For a 13' x 9' x 2" pan, start checking at about 30-35 minutes before removing from the oven.