Prepare cake batter and bake as directed on package for 24 cupcakes. Cool in pans 10 min. Pierce tops with fork.
Add boiling water to gelatin mix in small bowl; stir 2 min. until completely dissolved. Spoon over cupcakes. Refrigerate 30 min.
Melt chocolate as directed on package. Beat cream cheese and butter in large bowl with mixer until blended. Add chocolate and vanilla; mix well. Gradually add sugar, beating after each addition until light and fluffy.
Spread frosting onto cupcakes. Top with cranberries.