Combine applejack, grenadine, lemon juice, and bitters in a cocktail shaker.
Fill shaker with ice and shake vigorously until well chilled, about 15 seconds.
Strain into a chilled coupe or martini glass.
Squeeze lemon twist over surface of drink, skin-side-out to release fragrant oils.
Rub rim of glass with skin side of lemon twist and discard twist.
Serve immediately.
