Agar agar powder. It goes into vegan cheese. It goes into homemade vegan jelly (or jello, for north American readers). I used 3 cups of fruit juice and 1.5 teaspoons of agar agar powder (but maybe could have done with a tiny bit more – a reliable source tells me that if the juice is acidic then more agar agar powder will be needed). Bring to the boil, simmer for 5 minutes, then tip into dishes, small cups, whatever you like, to put in the fridge. The kids and I added some berries too.
We left the jelly to set overnight and it was delicious. So easy!