2 oz of Dark rum
3/4 oz of white rum (or Light Rum)
3/4 oz of Triple Sec
1/2 tsp of powdered sugar (or sugar)
1 oz of Lime Juice
2 oz of overproof rum
1/4 oz of Lime Syrup
Shake well over crushed ice in a shaker, and strain into a large highball glass over crushed ice.