Irish Whisky Cake Recipe

Substitute for instant pudding mix recipe?
I'm doing my second annual batch drunk cake recipe that I found on http://www.thatsmyhome.com/sweetspot/tipsy-irish-whiskey-cake.htm . It is a great recipe for an occasional baker like me, since it requires a packaged cake mix more + +, however, I forgot to buy the packaged instant pudding. The stores are all closed for Christmas now, is there a substitute I can use? Thanks in advance for your help!
I make a career flying to CVS for a bandage, if you have a room you can have pudding mix there. The secretary said they are open 24 / 7 until today and tomorrow. If not, the cake is there for moisture, if you can imagine a gelatin powder mixed with wet ingredients your cake mix, which in turn, the batter a bit thicker, and help the finished cake to celebrate together. Instead, add half cup of mayonnaise (basically egg and oil, vinegar fades out) and some more vanilla to detect the taste of the pudding that she gave.