Fill a rocks glass with ice and place in the freezer to chill.
Meanwhile, in a mixing glass, soak one sugar cube in 4 dashes of Angostura Bitters.
Add 2 ounces of Rye whiskey to the mixing glass and stir to combine.
Remove the glass from the freezer and discard the chilled ice.
Fill the chilled glass with ¼ ounces of Absinthe and slowly roll it around the glass before discarding.
Pour the Rye, bitters, and sugar mixture into the Absinthe-rinsed glass.
Garnish with a twist of lemon.