1. Add the gin, Suze, and Lillet or Kina L’Aéro d’Or a cocktail mixing glass. Fill glass halfway with ice and stir briskly until well-chilled.
2. Strain into a chilled coupe glass. Express the oils from the grapefruit zest over the top of the cocktail by squeezing the zest colored side down over the cocktail to spray the oil over the top of the drink, then drop the grapefruit twist into the glass.