Re: Liqueur question
Peppermint extract *IS* alcohol. Extracts are oils extracted in alcohol. Now, you will need much less of the peppermint extract than you would a liquor meant for drinking as it is much more concentrated. But I just wanted to clear that up... anytime you use peppermint or vanilla extract, you are using alcohol.
I think the advice to replace the vanilla with peppermint will work just fine. But, I'm sure you could google and find a recipe that specifically calls out peppermint extract.