2 1/2 tsp powdered gelatine
1 cup caster sugar
Pour 1/3 cup just-boiled water into a heatproof jug. Sprinkle over gelatine and whisk to dissolve.
Place sugar and 1/4 cup water in a small saucepan over a low heat. Stir until sugar dissolves then simmer (without stirring) for 1-2 minutes or until temperature reaches 125°C on a sugar thermometer. Remove from heat and stir in gelatine mixture.
Transfer mixture to the large metal bowl of an electric mixer and set aside to cool for 5 minutes. Beat on medium-high, using whisk attachment, for 6-7 minutes or until thick and fluffy.