Blend the peaches until smooth. Then, strain the mixture through a fine mesh strainer to remove pulp.
Add basil leaves to the pitcher. Then, gently muddle them to release the oils.
Pour the strained peach puree into the pitcher with the muddled basil.
Add lemon juice and simple syrup. Stir well.
Next, pour in cold water and mix until combined.
Refrigerate the mixture for 1-2 hours to let the flavors blend.
Fill glasses with ice and pour the mixture over.
Finally, top each glass with a peach slice and basil leaf.
Notes
Store the mocktail in the fridge for up to 3 days. However, note that the basil may darken after 24 hours.For best results, use ripe, fresh peaches. Frozen peaches work too - just thaw them first.To make simple syrup, heat equal parts sugar and water until dissolved. Let it cool before using.Add more or less simple syrup based on the sweetness of your peaches.If you want to remove the basil leaves, strain the drink again before serving.