In a cocktail shaker, add pineapple, Rosemary, lime juice and simple syrup. Muddle (mash) until pineapple is mostly liquid.
Fill with ice and add both alcohols. Shake.
Double strain using the cocktail shaker top and a small strainer.
Pour into chilled martini glass and garnish with a pineapple slice.
Notes
*Simple syrup - Boil equal parts of water and sugar until sugar has melted. Cool before use. This is a common cocktail ingredient - make a large batch and keep in the refrigerator for your next cocktail celebration.