What you need
1 teaspoon caster sugar
Juice from 2 limes, about 2 tots
2 tots white Rum, like Bacardi
2 tots soda water
4 mint leaves
1 sprig of mint and lemon slice to garnish
You should prepare this in a shaker or a really thick glass before transferring to a long slim collins glass.
Break up the mint leaves and toss them into the shaker, quarter the limes, squueeze out as much of the juice as you can and toss them into the shaker. Add the caster sugar and give the contents a crushing with a mortar or a wooden spoon. You get the idea, they need to be crushed to extract the last of the juice from the limes and to release the flavor from the mint.
Add the rum and and fill the shaker with ice.
Give it a good shake, remove the top and add the soda water and give it one last shake.
Pour everything from the shaker into the glass, garnish with a slice of lemon and man you in paradise