Classic Mai Tai

Fill a glass to the brim with crushed ice. Place more ice in a cocktail shaker; add white rum, lime juice, orange liqueur (or orange juice) and orgeat to the shaker. Cover and shake until chilled; strain into the prepared glass. Gently pour dark rum along the top of the drink (you can run it over the back of a spoon into the top of the glass to "float" it). Dust the top of the drink with cinnamon, then garnish with lime slice, mint sprig and/or flower, if desired.