Pour vodka, Campari, and Aromatic bitters into an ice-filled shaker. Shake well.
Strain drink into a chilled cocktail glass or serve on the rocks in an old-fashioned glass.
Garnish with a lemon twist.
An alternative to Campari is Aperol, which contains orange peel and rhubarb. Another one that could be substituted without much hassle would be bitters or Cynar, an artichoke-based liqueur with a bitter taste.