Mix and bake cake according to package directions, using two
9" cake pans. Cool in pans for 15 minutes; remove from pans
and cool completely on a wire rack. In a mixing bowl, beat
cream cheese, sugar, vanilla and salt until fluffy. Fold in
cream. Split each cake into two horizontal layers; place one
on a serving plate. Spread with a fourth of the cream
mixture. sprinkle with 1/4 of the chocolate. Repeat layers.
Cover and refrigerate 8 hours or overnight.