1) Cut the lemon into small cubes. Put all but 1 lemon cube, the basil, and brown sugar together in a glass and muddle until the consistency of a paste or jam.
2) Fill a glass with ice. Pour rum and sweet and sour mix into shaker without ice. Put cap on and shake; this blends the spirit with the mixer and creates a froth.
3) Strain into glass and stir. Garnish with small spring of basil and cube of lemon and serve immediately.