To make the infused gin (do this as far ahead as you can), strip the zest from the oranges, then add to a small pan with all of the remaining ingredients, except for the gin.
Gently bring to the boil, then simmer over a low heat for 8 to 10 minutes, or until it forms a light syrup. Take off the heat and leave to cool.
Once cold, pour the the cooled syrup and its infusions into a glass bottle and top up with the gin. Shake well to mix and store for at least a week to infuse. Strain before using.
To make the cocktails, divide a handful of ice cubes between two old fashioned whisky glasses. Mix the negroni ingredients in a jug, stir well and divide between the glasses.