Take four tumblers and pour the absinthe into the first one. Swirl around to coat the inside of the glass then pour into the next glass. Repeat until all the glasses have been coated with the absinthe. If there’s any left, divide it equally between all of the glasses.

Pour the sugar syrup, both types of bitters and whiskey into a large mixing glass or jug. Add 25ml cold water and a good handful of ice. Stir until the outside of the vessel feels really cold. Taste – if it’s too sweet or strong, keep stirring to dilute it further.

Strain into your prepared glasses. Twist a piece of orange zest over a glass to release a little of the citrus oils, then drop it in. Do this for each of cocktail just before serving.