This classic chocolate mayonnaise cake is probably the best moist chocolate cake recipe you will find anywhere. Chocolate cake is just about everyone's favorite and if you can make it easily at home, it is even better.
Combine flour, cocoa, baking soda and baking powder. Mix well and set aside.
Beat together eggs, sugar and vanilla in a large bowl for 3 minutes, using the high speed of an electric mixer. Mixture should be smooth and creamy. Reduce speed to low and beat in mayonnaise until blended.
Add flour mixture in batches, alternating with water, in 4 equal additions (1/4 of the flour, then 1/4 of the water etc). Pour the batter into the prepared cake pans.
Bake for 30 to 35 minutes, until the center of the cake springs back when lightly touched or until a toothpick inserted into the center of the cake is clean when removed. Cool in pans on a wire rack for 10 minutes. Remove from the pans and allow to cool completely before frosting with your favorite frosting.