Put the watermelon flesh in a liquidiser and blend until smooth.
Combine sugar and water to make a syrup.
Stir over low heat until the sugar dissolves.
Add some rind and let it boil for 5-8 minutes.
Allow to cool.
Strain the syrup and add to the fruit puree.
Pour into a tin and freeze for 20 minutes.
Stir the ice crystals into the liquid and freeze again.
Repeat the process every 20 minutes until the liquid is evenly frozen into crystals.
Keep frozen until required then spoon into individual serving dishes.,
Serve immediately with almond biscuits.