To make the lemongrass syrup, put the lemongrass and sugar in a pan, add 250ml (9fl oz) water, stir to dissolve the sugar then bring to the boil and simmer for at least 20 minutes. Take off the heat once it has a good sticky consistency, and stir in the lime juice.
Grill, griddle or barbecue the fruits until nicely seared. As they begin to soften, drizzle them wit