This drink is notoriously difficult to balance. With Plymouth gin, Luxardo maraschino liqueur, and the recently reintroduced Crème Yvette violet liqueur, these proportions work well, but using other brands may necessitate tweaking.
In a cocktail shaker three-fourths full of ice, combine 2 ounces gin, 1/2 ounce lemon juice, 1/2 ounce maraschino liqueur, and 1/4 ounce crème de violette liqueur. Shake well and strain into a cocktail glass.
