- 150 ml strained freshly squeezed lime juice
- 2 tbsp liquid glucose
- 1 tbsp grenadine
- 580 gm caster sugar
- 220 ml white rum
- Finely grated rind of 3 limes
- 4 eggwhites
- 10 titanium-strength gelatine leaves, softened in cold water for 3-5 minutes
- 60 gm pure icing sugar, sieved with 10gm cornflour
- 1Stir juice, glucose, grenadine, 400gm sugar, 150ml rum and two-thirds of the rind in a small saucepan over medium-high heat until sugar dissolves, then bring to the boil and cook until syrup reaches 127C on a sugar thermometer (8-9 minutes). As syrup nears temperature, whisk eggwhite and a pinch of salt in an electric mixer until soft peaks form, then gradually add remaining sugar and whisk until glossy. When syrup reaches 127C remove from heat, squeeze excess water from gelatine and stir into hot syrup to dissolve. Whisking on low-medium speed, gradually add syrup to meringue, then whisk on high speed until thick and cooled to room temperature (10-15 minutes). Add remaining rum and whisk to combine. Spoon into a lightly oiled 20cm-square cake tin lined with baking paper, smooth top and stand at room temperature until set (3-4 hours). Turn out onto a piece of baking paper dusted with a little icing sugar mixture, peel baking paper off base and cut marshmallow into cubes with a sharp knife dipped in hot water, then wiped dry.
- 2Combine remaining icing sugar mixture with remaining lime rind in a large airtight container, add marshmallows, shake to coat and store at room temperature for up to 2 weeks.