220 gm (1 cup)caster sugar1½titanium-strength gelatine leaves, softened in cold water for 5 minutesScrapedseeds of 1 vanilla bean500 gmthick plain yoghurtSegments of2 limes, juice of ½½Lebanese cucumber, unpeeled, thinly sliced widthways on a mandolinTo serve:honeydew melon, scooped into balls with a melon-ballerCucumber jelly110 gm (½ cup)caster sugar1titanium-strength gelatine leaf, softened in cold water for 5 minutes2Lebanese cucumbers, unpeeled, coarsely chopped
Stir sugar and 120ml water in a small saucepan over medium heat until sugar dissolves, then bring to the boil. Remove from heat, pour half the syrup into a bowl and set aside. Squeeze gelatine to remove excess water then add to remaining sugar syrup with vanilla seeds, whisk to combine and set aside.
Whisk yoghurt in a bowl until smooth, then whisk in gelatine mixture, divide among six 200ml serving bowls and refrigerate until set (2-3 hours). Add lime segments and juice to reserved syrup and refrigerate until required.
For cucumber jelly, stir sugar and 60ml water in a small saucepan over medium heat until sugar dissolves, then bring to the boil. Remove from heat, squeeze gelatine to remove excess water then add to syrup and whisk to combine. Process cucumber and syrup in a food processor until finely chopped, pass through a muslin-lined sieve into a bowl (do not press on solids) and set aside to cool slightly (15 minutes).
Arrange cucumber slices over yoghurt mixture, pour cucumber jelly over and refrigerate until set (1-2 hours). Top jellies with melon balls, drizzle with lime syrup and serve.