Greetings, comrade. This quasi-revolutionary sorbetto is so bone-chillingly good that there’ll never need to be another cold war. It’s one of the flavors we were developing for our ‘Dictators of Cool’ collection, which included our old favorites Adolf Hitler (The Great Licktator), Colonel Gaddafi (Cone El Gaddafi), and David Cameron (Fake 99). — Matt O'Connor, The Icecreamists
Pour the water into a saucepan and add the sugar. Place over a low heat and bring to the boil, whisking often, until the sugar dissolves. Reduce the heat and allow to simmer for 5 minutes, continuing to whisk until the liquid turns into a syrup.
Pour the syrup into a heatproof bowl and set aside for about 30 minutes, stirring occasionally, until cooled to room temperature. For more rapid chilling, half-fill a sink with cold water and ice and place the bowl of mixture in it for 20 minutes. Pour the tonic water into a bowl, add the sugar syrup, then cover and refrigerate, ideally overnight, until thoroughly chilled (at least 4 degrees C).
Add the gin, lime juice and lemon juice to the chilled mixture, then pour into an ice cream machine and churn according to the manufacturer’s instructions.
When the churning is completed, use a spoon or spatula to scrape the sorbetto into a freezer-proof container with a lid. Freeze until it reaches the correct scooping texture (at least 2–3 hours).
Decorate each portion with lime slices and serve.