Watermelon ice cubes
Cut the melon into cubes, tear off the peppermint leaves.
Divide the melon and peppermint leaves between the ice cube moulds, fill with water, cover and freeze for approx. 2 hrs.
Squeeze the juice from the lime, cut the melon into cubes.
Bring the water and lime juice to the boil with the watermelon. Reduce the heat, cover and simmer for approx. 30 mins., leave to infuse on the switched-off hob for approx. 10 mins., puree.
Pass the liquid through a sieve (yields approx. 800 ml).
Bring the juice and sugar to the boil while stirring, cook over a medium heat for approx. 20 mins., skim off the foam (yields approx. 700 ml of syrup).
While still boiling hot, ladle the syrup into the prepared jars and fill to just below the rim, seal immediately, leave to cool.
Spoon 1½ tbsp of syrup into each glass, fill with water.
Rinse the lime in hot water, cut in half and slice. Add 3 ice cubes to each glass, garnish with lime and mint.