1 1/2 oz of Dark rum
1/2 oz of creme de cassis (or blackcurrant-flavored liqueur)
1/2 oz of dry vermouth
1 3/4 oz of Pineapple Juice
6-8 oz of club soda (or clear soda)
Shake everything except the soda with ice; strain into a cocktail glass. Fill with soda.