INGREDIENTS

8 oz.  Sugar  
8 oz. Dark Brown Sugar , firmly packed 
4 oz.  Water  
4 oz. frozen Pineapple Juice Concentrate, thawed 
2 oz.  Butter , unsalted 
3 oz. Dark Rum  

DIRECTIONS

1.) Combine first 5 ingredients in heavy medium heat until sugar dissolves. Lightly boil until reduced to 1 cup, about 10 minutes. Cool to lukewarm.

2.) Mix in rum. Keep covered and refrigerate. Reheat to lukewarm and whisk before serving.