1 oz. (30 ml) fresh lime juice
¾ oz. (22 ml) simple syrup (1:1, see headnote)
2 dashes Angostura bitters (optional)
Combine all the ingredients in a cocktail shaker filled with ice and shake vigorously for 15–20 seconds, or until frosted on the outside.
Double strain into a coupe.
Garnish with a mint leaf.
For an East Side, muddle a few cucumber slices with the mint and garnish with a fresh cucumber slice.
Substitute vodka or tequila for the gin.
Serve in a highball glass over fresh ice and top with club soda.
Add 1–2 dashes of absinthe to make the French Pearl cocktail.