1 barspoon fine white sugar
Add sugar and lime juice into a highball glass.
Gently muddle the sugar into the lime juice until it just emulsifies.
Add three or four leaves of fresh mint and gently muddle into the sugar/lime juice.
Add the rum and vigorously stir to combine everything.
Top the glass with fresh ice and a squirt of lime juice.
Garnish with a sprig of mint and two or three lime wheels, serve.