1. Cut the apple and remove the core.
2. Transfer the apples to a container, add a little water and blend them very well.
3. Bring a pot to medium heat.
4. Pour the apples into the pot and add the agar agar.
5. Let it cook for 5 minutes, while continuing to stir.
6. Remove and let cool at room temperature.
7. Beat the preparation at maximum speed for 12 minutes, until it doubles in size.
8. Pour the mixture into a mold and refrigerate for at least 4 hours.