Shake the absinthe, grapefruit juice, and elderflower liqueur with ice, strain into a flute with 2-3 oz dry sparkling wine, and garnish with a grapefruit twist.
I have since done this with the elderflower split 50:50 with honey syrup (1:1) with good effect.
At work, the general manager of Menton (our sister restaurant) asked if there was a secret to making the Death in the Afternoon a good drink. I replied that there really was not; basically, either you enjoy the combination or you do not. Then that evening at Drink, a guest asked for an absinthe cocktail. I then recalled how well absinthe paired with pink grapefruit juice via one of the drinks at the Kübler Absinthe release party here in Boston pushed on me by woodland nymph characters circa October 2007. With that, I added elderflower liqueur to take the mix in a Bohemian direction, and cava to circle back to the conversation earlier that afternoon. For a name, I dubbed this one The End of Something after a short story by Ernest Hemingway as a nod to the Death in the Afternoon inspiration.