Hi, Ok so i made a baileys cake with baileys buttercream the other night and the next afternoon when we had some there was no taste or smell of balieys at all!! I've made this buttercream before and never had this problem but saying that the cakes never lasted more than an hour, this is the thing am making one next week for a birthday and covering it in foundant, do you think the foundany covering with stop the baileys from evaporating and keep the taste/smell in the buttercream??

Are you 150% SURE you measured all ingredients right?  Did you have something interupt you when putting it together?   Maybe you need to add a bit more Bailey's.  It's been sooo many years since I've made one I can't remember the recipe or how it tasted the next day.