Bake the cake as directed in a 9×13″ pan. Let cake cool completely. Poke holes in cooled cake. Mix 1 package orange gelatin dessert with 1 c. boiling water and 1 c. cold water. Pour over cake. Cover and refrigerate for 4 hours.
Mix pudding mix with cold milk the other package of orange gelatin dessert and vanilla. Beat by hand with a whisk until thickened. Fold in the whipped topping. Frost the cake with the pudding mixture.
For a layered Creamsicle Cake: Make the cake batter as directed, then batter pour evenly into 3 round 9″ cake pans. Bake cakes as directed and let cool. Then, make the orange gelatin as directed on the package — but with this version, you’ll let the gelatin set up instead of pouring it into the cake. We recommend using your round cake pans, or using a 13×17″ jelly roll pan (1″ deep cookie sheet with edges). Once you pour the liquid gelatin mixture into the pans, it will need to be refrigerated for about 4 hours. Meanwhile, make the pudding mixture according to the original recipe. Finally, layer in this order: cake, gelatin pudding mixture. Repeat once more for a 6-layered Creamsicle Cake.