Instructions:

In an old fashioned glass, muddle the sugar cube with a few drops of water to make a paste. Add the bitters and stir until dissolved.

Coat the inside of a second old fashioned glass with the absinthe or pastis by rotating it around so that all sides are covered. Discard any excess liquid in either glass once coated.

Fill both glasses with crushed ice and empty one into the other (the one without absinthe).

Pour in two ounces of tequila, swirl gently, and strain into prepared glass over fresh ice cubes if desired; discard remaining ice from first glass without any drink poured out from it).

Garnish with lemon peel and serve immediately