1. In the blender, process the cherries with 8.5 fl oz of water.
2. Pour the mixture into a saucepan and add the sweetener.
3. Bring to a boil over medium heat.
4. Dilute the agar agar in 1.5 fl oz of water and add it to the saucepan.
5. Mix for 3 minutes while boiling.
6. Pour the mixture into a mold.
7. Let cool to room temperature and then refrigerate for 6 hours.