Preheat your oven to 350°F (175°C) and lightly grease & flour two 9-inch round cake pans. In a medium bowl, whisk together cake mix, baking powder, all-purpose flour, granulated sugar, dairy milk and water until fully blended.
Take a separate bowl and beat cocoa powder, vanilla extract and egg whites until fluffy. In yet another bowl, mix together the instant chocolate pudding mix, vegetable oil, milk, cream cheese and butter until velvety smooth.
Pour the batter into your prepared cake pans and bake in preheated oven for approximately 25 minutes or until a toothpick inserted in the middle of each cake comes out clean. Allow cakes to cool in pans on a wire rack for 10 minutes before inverting them onto the wire racks to cool completely.
To prepare the frosting, cream together confectioners' sugar and butter until light and fluffy. Spread evenly over cooled cake layers and refrigerate for one hour prior to serving.