Step 1

Preheat oven to 350°F. Coat two 9-inch round baking pans with cooking spray. Set aside.

Step 2

Mix flour, sugar, cocoa powder, baking powder, and baking soda together in a bowl. Add mayonnaise and blend to combine.

Step 3

Add water and vanilla extract and blend until batter is smooth. Pour batter equally into two prepared baking pans.

Step 4

Bake for 30-40 minutes or until a cake tester inserted in the middle of each cake comes out clean.

Step 5

Cool completely. Place one cake on bottom of serving tray. Add a layer of frosting as a filling. Top with second cake and cover with remaining frosting.