2 oz favorite rum
.75 oz lime juice
.5 oz simple syrup

2 lime halves
4 sugar cubes
2 oz favorite rum

Author's choice:
1 oz Clément Première Canne Rhum Agricole
1 oz Smith & Cross Traditional Jamaica rum
.75 oz lime juice
.5 oz turbinado syrup

Tools - Shaker, jigger, ice, hawthorne strainer, fine strainer
Glass - coupe
Ice - none
M.o.P -
(method 1) build, add ice, shake and double-strain
(method 2) muddle lime and sugar, add rum and ice, shake and double-strain
Garnish - none