1	Divide lemonade among twelve ½-cup capacity dariole moulds or disposable cups and stand for 10 minutes to allow bubbles to subside. Place on a tray and freeze for 2-3 hours, then insert an iceblock stick into each one and freeze overnight.
2	In a food processor process the passionfruit pulp and vanilla bean to crack passionfruit seeds, then pass through a fine sieve into a bowl, discarding solids. Measure 210ml of passionfruit juice and combine with sugar syrup, lime juice and 2/3 cup water. Refrigerate until cold, then divide among moulds or cups with lemonade and freeze overnight. Unmould and serve.

Note To make sugar syrup, combine an equal quantity of sugar and water in a saucepan and boil for 1 minute. One cup each of sugar and water will make 1½ cups sugar syrup which will keep indefinitely refrigerated in a sterile container.