For a non-alcoholic version, replace the gin with 150ml elderflower cordial.
8 unwaxed organic lemons, cut into chunks
300g caster sugar
Sprig of fresh mint
Put the lemons into a blender or food processor with 50g of sugar and 250ml of water. Blitz until smooth.
Pour the juice through a sieve into a jug and tip the lemon pulp back into the blender. Add another 50g of sugar and 250ml of water and repeat the process until all the sugar has been used up.
Discard the pulp and stir the gin into the jug. Keep refrigerated until decanting into a chilled container and add a sprig of mint.