2 oz Grapefruit juice (pink)
1 bsp Simple syrup
1 bsp Lemon juice
1 oz Aromatized wine, Lillet Rouge (or Carpano Antica; as float)
2 ds Grapefruit bitters (as float)
Shake, strain over rocks in a highball, top with fortified wine and bitters.
Maggie Hoffman of Serious Eats recommends Carpano Antica Formula vermouth in place of the Lillet Rouge. You could also try Dubonnet, Byrrh, Bonal, etc.
Ehren Ashkenazi, The Modern, NYC.
Rye, Aromatized wine, Grapefruit bitters, Grapefruit juice, Simple syrup, Lemon juice