Preheat the oven to 200°C.
Soften the butter to room temperature and then mix with the sugar. Mix together and then add the flour. Beat together until you have a smooth mixture. Roll the mixture into large sausage-like shapes and refrigerate. Once hard, cut the pastry into 1cm thick rounds. Place the rounds on a silicone baking sheet, transfer to the oven and bake for 8 minutes.
Place the fondant icing in a bowl soften over a pan of simmering water (bain-marie). Add the lime juice to the icing and combine. Pour the icing into a piping bag.
Remove the biscuits from the oven, allow to cool and then decorate with the lime scented icing. Grate the zest of the lime on to the biscuits and finish with a sprinkling of the popping candy.
«Take care not to overheat the fondant icing in the bain-marie, it just needs to be softened.»