2 oz gin
1 oz lime juice (or lemon if you prefer)
1/2 oz simple syrup
5 or 6 fresh mint leaves (plus one more for garnish)
Combine everything with ice and shake. Strain* into a coupe glass and garnish with a whole fresh mint leaf.
*Note: I recommend double straining (straining the drink through a fine-mesh sieve) to catch any shredded mint
There are three very different and yet very common origin stories for this prohibition era classic.
One story claims that it was invented in Chicago and named for the South Side neighborhood. Supposedly it was invented specifically to mask the flavor of bad quality gin that was available at the time.
Another story claims that it was invented several years before Prohibition at the Southside Sportsmen’s Club in Long Island, a private club where upper crusty Manhattanites went to hunt, fish and drink Mint Juleps. Some people claim that this cocktail may have evolved out of the mint juleps they served, even though the only thing this has in common with a mint julep is the mint.
Yet another popular origin story says that the South Side was invented at the 21 Club in New York. While 21 definitely poured countless South Sides during prohibition, a recipe for a very similar cocktail called a South Side Fizz appeared in print in 1916 and the 21 club didn’t open until 1922. So, it’s more realistic to say that 21 popularized the South Side but didn’t actually invent it.
As for the South Side Fizz, that recipe is very similar to this one, but it actually calls for both lemon and lime juice, and adds soda water. The use of both lemon and lime in the Fizz recipe is probably why both citrus juices are used interchangeably today.