Choose a spirit that is neutral in both flavor and fragrance, and preferably perfectly clear, too. In Italy, you can easily buy 190° proof (95% alcohol) in the supermarket for the purpose of making homemade liqueurs, but this isn’t available in many other countries. Everclear is close; unflavored vodka works just fine. If using a 190° proof alcohol, you should make slightly more syrup to dilute the liqueur sufficiently – 7 fluid ounces of water and 5½ ounces of sugar. The resulting liqueur should be around 37–40% alcohol, which is as strong as you would want a drink like this!
Add herbs and orange peel (make sure there is no white pith as it is too bitter) to the alcohol in a glass bottle or jar and leave to infuse in the fridge for 1 week, agitating once a day. You will notice it looks fluorescent green – I love this color that the liqueur draws out of the bay leaves, but unfortunately it turns darker as it ages.
Make a simple sugar syrup by combining the sugar and 5 fl oz of water in a saucepan and bringing to the boil. Let it simmer for 10 minutes, then allow it to cool completely. Add the cooled syrup to the alcohol and herb mixture. Leave to infuse for 1 more week, then filter the alcohol through a fine sieve lined with muslin (cheesecloth).
Pour into a glass bottle and let it age in a cool, dark place for 3–4 weeks before serving for the first time. If it is still a little cloudy, you can filter again if you wish. If you leave it cloudy, just remember to shake the bottle a little before serving. Makes 2 cups.
Serve chilled and neat in small glasses to sip after a meal.