Pour 1 glass of mineral water into a blender jar. Then squeeze the lemon or lime and pour half of the juice into the water. Put 1 small handful of basil leaves in the blender jar.
Purée thoroughly with a hand blender. If it is too acidic, sweeten it with raw sugar, honey or other sweeteners if necessary - I always drink it without sugar. Pour in the rest of the mineral water slowly to avoid foaming.
I am very keen to experiment, so I always try out variations - e.g., fresh peppermint leaves instead of basil or a mixture of both.
A dash of juice is also delicious - e.g., cherry, apple, orange or mango juice - everything that is there that the juice counter offers.