Pour the water and sugar in a stainless steel saucepan. Bruise the leaves by scrunching them in your hands then place them in the saucepan. Bring slowly to the boil, stirring to dissolve the sugar.
Simmer for 3-4 minutes, turn off the heat and allow to cool. Add the lemon juice, then strain.
Pour the liquid into your ice cream maker and churn until you have a scoop able consistency. Pop in the freezer for 2-3 hours. Or Pour into a freezer container & freeze for 1.5 hrs then mix up with a whisk to break up and incorporate the ice crystals (which will be starting to form at the edges) before returning to the freezer. Keep mixing the sorbet once an hour for 4 hours to break up the ice crystals. Stop mixing when firm but still scoop-able.
I guarantee you’ll love it, the flavour is incredible.