Muddle blueberries in a small glass, then add fruit to shaker along with ice and all ingredients. Shake well, then strain into a coupe glass and garnish with a lime peel.
Editor’s Note: Maraschino liqueur, an ingredient in the Purple Rain, is not akin to the neon-colored cherries of the same name. It is, instead, a clear liqueur distilled from crushed sour cherry pits. A worthy addition to a home bar, it’s essential in the Hemingway Daiquiri and currently a favorite among mixologists for adding complexity and depth to many a concoction.