Heat all the ingredients except the gelatine and lime zest and juice in a saucepan over a medium heat until simmering. Remove from the heat.

Meanwhile, soak the gelatine in cold water for 5 minutes, or until soft. Squeeze out any excess water and add to the pan. Stir until the gelatine has dissolved. Remove from the heat and stir in the lime juice.

Chill for 4–6 hours, or until set. Grate over coconut and lime zest to serve.