For 2 x 750ml bottles
3 unwaxed lemons (or oranges)
900ml boiling water
850g white sugar (granulated or caster)
30g citric or tartaric acid
With a swivel potato peeler, cut thick ribbons of rind from the fruit, leaving the white pith behind.
Put the rind into a heatproof bowl and pour over the boiling water. Stir in the sugar, keeping the water moving until the sugar has all dissolved.
Leave the mixture to cool and then add the juice from the lemons (or oranges) and citric acid, and leave everything to steep overnight.
Next day, strain the rind away and bottle the cordial.
I poured mine into a 2 pint plastic milk carton and froze it. The remaining cordial is sitting in the fridge and is lovely. I also made it with oranges as I'd already used up all my lemons on another recipe, which I'll be adding in a moment!
Taken from: Sarah Raven's Garden Cookbook