So, I am making a cake for my wife's best friend. I decided to make her a COACH bag cake. I am very new to cake decorating and up until now have only used store bought frosting and made my own buttercream frosting once. I would really like to use either a chocolate buttercream, chocolate ganache or chocolate fudge filling, but don't know the best way to go about it. Any ideas would be greatly appreciated. Thanks.