- Put the sugar in a large saucepan with 1.5 cups of water. Bring to a simmer then add the lemon zest and juice followed by the blackcurrants. Cook the mixture over medium heat until the blackcurrants start to soften and burst.
- Pour the mixture through a sieve lined with muslin into a clean, heatproof jug then transfer to sterilized bottles. Keeps in the fridge for up to 1 month.
- Serve approximately ⅛ cup of cordial per ½ cup sparkling or still water, or dilute to taste.