Oh blood orange season, you come and go so quickly.
I had a surplus amount (it was an accident, I swear) but a friend shared a secret - blood orange juice + cider vinegar + sugar = blood orange shrub, a drinking vinegar which is great mixed with soda or tonic water, mayhaps a splash of gin on a Friday evening.
Obviously, I took some photographs whilst making this because I have a blog and blood oranges are famous on the internet. I really can't remember/find the website I got the recipe for this from - but I did take a photograph of it written in my notebook.
1 cup blood orange juice 3/4 cup cider vinegar 1 cup sugar (tbh I would probably put less than this in next time)