Place 10 mint leaves, a quarter of lime into a highball glass and muddle
Fill the highball glass to the top with crushed ice
Pour in 0.75 oz of sugar syrup, 0.75 oz of limoncello, 1 oz of dry vermouth and 1.5 oz of white rum
Top up with club soda and stir gently
Top up with crushed ice
Garnish with 1 dash of Angostura bitters and a mint sprig