Prepare and bake chocolate cake as directed on package. Bake in 2 - 9 inch round pans. Allow cakes to cool. When cakes are cool, cut each one in half with a long serrated knife, making four layers.
In a large bowl, combine cream cheese, brown sugar and vanilla. Beat until soft.
In a separate bowl, whip cream to soft peaks, then fold into cream cheese mixture.
Place the bottom layer of cake on the serving plate. Spread 1/4 of the filling on cake layer, then continue to stack up layers with 1/4 of the filling on each layer. Finish top with the final 1/4 of filling and grate the chocolate on top. Refrigerate for 6 hours before serving.