You'll need a one-litre siphon gun and three cream chargers to whip the yoghurt, but it's also pretty tasty simply whisked and served in dollops.
- 750 gm thick Greek-style yoghurt
- 6 gm xanthan gum (see note)
- 250 gm each watermelon and rockmelon, scooped into balls with a melon-baller
- 100 gm papaya, scooped into balls with a melon-baller
- 125 gm raspberries (about 1 punnet)
Musk and raspberry syrup
- 200 gm caster sugar
- 2 musk sticks
- 60 gm frozen raspberries
- 60 gm liquid glucose
- ¼ tsp rosewater
- 1For musk and raspberry syrup, combine ingredients and 200ml water in a small saucepan over medium heat and bring to the boil, stirring to dissolve sugar and musk sticks (5-10 minutes), then set aside to cool.
- 2Combine yoghurt, xanthan gum and 150ml musk and raspberry syrup (reserve remainder) in a blender and blend to combine. Transfer to a chilled 1-litre siphon gun, seal, charge with 2 cream chargers and shake vigorously. Pipe a little mixture to test consistency: it should be that of whipped cream; if not, add an extra charger and shake again.
- 3Combine fruit and remaining syrup in a bowl, divide among chilled glasses, pipe yoghurt mixture over and serve immediately.
Xanthan gum, a stabilising agent, is available from health-food shops.