Avoid leaving the sheets in the water for too long, or they will break down.
You can also use 1 tablespoon of Agar flakes instead. Soak the Agar flakes in water for 30 minutes first. Drain the water and squeeze the extra moisture out of the flakes. Add the flakes to 2 cups (450 milliliters) of water and cook for 2 minutes. Agar is made from seaweed. You may also find it labeled as: Agar-Agar, China grass, or kanten. [6] X Research source
You can also use half-and-half instead of heavy cream. This will give you a lighter panna cotta. Keep in mind that gelatin made with dairy may take longer to set.
Be careful when adding topical fruits, such as figs, ginger, kiwi, papaya pineapple, and prickly pears. The enzymes in these fruits will keep the gelatin from setting. [10] X Research source If you want to use these fruits (with the exception of kiwi) in gelatin, you will need to peel, cut, and boil them for five minutes before adding them to the gelatin. Kiwi should not be used in gelatin. Even peeling and boiling it will not get rid of the enzyme.
Try chilling the mold in the fridge for a few hours until you are ready to use it; this will help the gelatin set even faster.