1 1/2 oz of Light Rum
1 tbsp of Passion-fruit Syrup
1 oz of Orange Juice
1 oz of Lime Juice
1 tsp of 151 proof rum (or overproof rum)
Combine ingredients with 1/2 cup crushed ice in an electric blender. Blend at a low speed for a short length of time. Pour into an old-fashioned glass and serve.