Prepare cake as directed on box, and add sour cream, pudding and chocolate chips. Pour into 2 9-inch round baking pans. Bake as directed on box (you might need to add a minute or two to the baking time because of the added ingredients). Place on a wire rack to cool. Equally Impressive Chocolate Frosting 1 cup butter at room temperature 3 oz. Ghirardelli 100% cocoa chocolate bar 4-5 cups powered sugar milk Chop the chocolate, then place in double boiler until melted. Cream together butter, chocolate, and 4 cups of powered sugar. Add milk as needed for desired consistency. Combine until creamy; continue to add powered sugar and milk until it is the consistency and taste that you want. Place one layer of cake on cake stand and frost the top, then add the second layer and frost the rest of the cake. Garnish with chocolate curls. I like to make bigger curls for this cake. Melt some chocolate, get a 9 inch round cake pan and turn upside down and then spread the chocolate on it as a thin, thin layer. Let cool until the chocolate is set and then get a cheese slicer or potato peeler, and slice the chocolate into curls.