Blackcurrant syrup (known as cassis in France) is most commonly used as an addition to drinks. The most popular being a kir (cassis and white wine) and kir royale (cassis and champagne). Both are delicious!
We have an abundance each year from the blackcurrant bushes we planted about 8 years ago. I make the syrup and then put it in sterilized bottles and keep in the fridge. The kids love it mixed with some water, Perrier or Sprite (as shown in the photo here).
Place all ingredients in a large pot over medium-high heat. Bring to a simmer and then turn heat to low and gently simmer for two hours, stirring every now and then.
Remove from the heat and let it cool slightly. Strain through a fine mesh strainer. Transfer to a sterilized bottle and keep in the fridge.