Oh how I fell in love with Guavaberry Island Folk Liqueur during a visit to Sint Maarten over 10 years ago! We mostly drank it by adding a splash to our Champagne (big surprise!) but it can also be used to make several other yummy cocktails and food dishes too! Follow this link to their recipe page.
I don't seem to be able to order the product online, but I have Total Wine looking for it for me and I've submitted a contact form to the site to see if they'll ship some to me! Once I find it - I'll let you know! I can't wait! In the meantime, if you visit Sint Maarten, make sure you stop by the Guavaberry Emporium on Frontstreeet - you won't regret it!