Bring the water to the boil, add the zest of a lemon and the sugar and simmer gently for about 2 minutes. Remove the peel and allow the mixture to cool.
Add the juice of the two lemons and chopped basil leaves - leave some for decoration.
Place the liquid in the freezer for approx. 1 - 2 hours (cool down until just before freezing.
Beat egg whites into snow and fold in carefully.
Then put the mixture in the ice cream maker for about 20 minutes. Then serve garnished with basil leaves.