Soak the sugar cube with the bitters and place in the bottom of a highball glass. Mash with the back of a spoon (or muddler, which we hope has not been used to make a Mojito), add the rye whiskey and fill the glass with ice. Stir for about 30 seconds and then strain into another lowball glass that has been rinsed with Absinthe and filled about halfway with ice. Garnish with a lemon twist.