From http://backyardbartender.blogspot.com/2011/06/mxmo-lviii-carmen-..., yet another way to use Poire William, this time with balsamic syrup:

1 oz Poire William eau-de-vie
1 oz cachaça (I might sub in a darker rum here?)
1/2 oz balsamic syrup (Make it from scratch with her recipe here: http://backyardbartender.blogspot.com/2010/10/el-sangre-de-fresa..., or buy it at a gourmet grocery store)
1/2 oz Cointreau
1/2 oz fresh-squeezed lime juice
dash of orange bitters
club soda