- In a small saucepan, bring all the ingredients to a boil and simmer until the sugar has dissolved. Pour into a bowl. Refrigerate until the syrup has completely chilled. The citrus syrup will keep for about three months in the refrigerator.
- In a highball glass, pour the liquor, citrus syrup, Angostura and water. Stir with a spoon.
- Fill the glass with ice cubes and garnish with the orange zest and maraschino cherry.