Add 120ml (½ cup) gin to a saucepan along with the sugar and simmer to reduce by two thirds.
Combine the biscuit crumbs and melted butter and press into the base of a 10cm (4in) metal ring, taking care to keep it crumbly and not over bash it until it becomes dust!
Zest your citrus fruits and set aside. Retain a little of each for the garnish. Whisk th