South Side (cocktail)

A South Side or Southside is an alcoholic beverage made with gin, lime juice, simple syrup and mint. A variant, the Southside Fizz, adds soda water.
History.
Its origins are subject to speculation. It has been proposed that it gets its name from either the South Side district of the city of Chicago, Illinois, or from the Southside Sportsmen's Club on Long Island.
The drink may have been the preferred beverage of Al Capone, whose gang dominated Chicago's South Side. The gin imported by Capone's rivals on the North Side of Chicago was smooth, and usually consumed with ginger ale. However, the gin consumed by Al Capone's gang had a rougher finish, and required more sweeteners to make it palatable. Thus the South Side was born.
21 Club recipe.
The following recipe for a South Side is used by the famed 21 Club in New York City.
Ingredients:
Combine all ingredients except mint into a cocktail shaker, fill shaker with ice, and shake well. Open the shaker and add the mint, leaving one mint leaf around the size of your thumb for garnish. Close the cocktail shaker and roll the mint leaves from one end of the shaker to the other so as to gently release the mint oils but not to bruise the leaves. Strain the glass into a highball glass and garnish with a mint leaf.
South Side Fizz.
A South Side Fizz adds soda water:
In a shaker, combine the mint, lime juice, and simple syrup. Add the gin and fill with ice. Shake, and strain into a highball glass filled with crushed ice. Stir until frost appears on the outside of the glass. Fill with club soda and garnish with another dash of mint.
Related drinks.
The Tom Collins does not include mint, and is carbonated.