When done, let cool 20 min. Poke holes all over cake with fork.
Dissolve Jell-O in 1 cup boiling water. Add 1 cup cold water. Pour slowly over cake to allow it to run into holes. Refrigerate cake for 2-3 hours.
For frosting, in large bowl, beat cream cheese until fluffy. Add dry jello, pudding mix, milk and vanilla. Beat well. Fold in cool whip and spread on cake.
Variation: you could use lemon cake mix and lemon jello.