Chocolate Mayonnaise Cake with Sour Cream Frosting

Ingredients

• 0.3 teaspoon double-acting baking powder 
• 1.8 teaspoons baking soda 
• 4 cups confectioners' sugar sifted
• 0.8 cup tablespoon dutch-process cocoa powder dark (Hershey's )
• 3 large eggs 
• 1 teaspoon espresso powder 
• 10.1 oz flour all-purpose
• 7 oz granulated sugar 
• 0.5 cup brown sugar light packed (4 oz)
• 1.3 cups mayonnaise 
• 0.3 teaspoon salt salted (omit if using butter)
• 0.5 cup cup heavy whipping cream sour room temperature
• 10.5 tablespoons butter unsalted softened cut into chunks and
• 0.8 cup cocoa powder unsweetened
• 2 teaspoons vanilla extract 
• 1.3 cups water 

Equipment

• bowl
• sauce pan
• oven
• mixing bowl
• wire rack
• baking pan
• stand mixer

Directions

1. Preheat oven to 350 degrees F. Spray two 9×2 inch round metal baking pans with flour-added baking spray (
2. Baker’s Joy) and line the bottom with circles of parchment (just to be safe!).In a large saucepan, boil the water.
3. Remove from heat and add the espresso powder and cocoa powder. Stir until smooth and set aside.In the bowl of a stand mixer, beat the eggs, sugar and brown sugar for a full 7 minutes or until thick and light.
4. Add the mayonnaise and vanilla and beat on medium until combined.In a second bowl, thoroughly mix together the flour, baking powder, baking soda, cocoa powder and salt..
5. Add to the egg mixture and stir until mixed.
6. Pour in the cocoa mixture and stir well. Batter will be thin.
7. Pour into prepared pans and bake on center rack for 30 minutes.
8. Remove from oven and let cool on a wire rack for 10 minutes. Invert cakes on a cooling rack, peel away the parchment (if you used it), and let cool completely.To make the sour cream frosting, beat the butter and cocoa powder in a large mixing bowl until mixed. Gradually add the confectioners’ sugar (and salt, if using) and sour cream and beat until smooth. Beat in the vanilla.