1. Blend the strawberries very well until you get a consistent puree.
2. Pass the puree through a strainer.
3. Pour the preparation into a pot, add the agar agar, sugar or sweetener of your choice, and cook over medium heat for 3 minutes.
4. It's important to stir constantly to prevent the preparation from sticking.
5. Pour the mixture into molds or an ice cube tray.
6. Let it cool at room temperature and then refrigerate for a couple of hours.