1 1/2 oz of bacardi silver rum (or Vanilla Rum)
1/2 oz of Lime Juice
1 oz of Bacardi 151 rum (or overproof rum)
1/2 oz of blue curacao liqueur
Mix all ingredients together with an ice cube or two, shaking vigorously and pour into a highball glass over 3 - 5 ice cubes. Serve.