This recipe comes from Allen Katz, host of "The Cocktail Hour" on Martha Stewart Living Radio.
Coat a well-chilled old-fashioned glass with absinthe. Discard most of the remaining liquid, leaving just a little in the bottom of the glass.
Add the sugar cube and soak with bitters.
Muddle sugar so that it dissolves in the glass. Add whiskey, stir, and garnish with a lemon peel.