Add the white rum, curaçao, lime juice and orgeat into a shaker with crushed ice and shake lightly (about 3 seconds).
Pour into a double rocks glass.
Float the dark rum over the top.
Garnish with a lime wheel and mint sprig.
Notes
Orgeat is a non-alcoholic almond syrup used in place of simple syrup. The drink is best when using orgeat but if you don't have it, you can substitute it with simple syrup.