Juice lemons. Add tartaric acid and stir to combine.

Add sugar and water to a saucepan, along with the mint leaves and the zest from about 1/2 of the lemons. Stir over medium-high heat until the sugar dissolves and the mixture just starts to simmer. This should take about 5 minutes. Remove mixture immediately once it starts to simmer.

Pour sugar mixture over lemon juice and leave for 15 minutes.

Strain mixture using a muslin cloth, pour into a bottle and place the lid on the bottle.

Allow to cool and store in the pantry for up to 12 months. Or pop it in the fridge to enjoy immediately.

Enjoy mixed with water or soda water, using 1 part cordial and 4 or 5 parts water.