8ml (1/2 tbs.) cold water
4.5g (1.5 tsp.) powdered gelatin
120ml (1/2 cup / 8 tbs.) heavy cream
100ml (6.5 tbs.) water
15g (1 tbs.) xylitol or erythritol
1/4 tsp. vanilla extract (optional)
1/16 tsp. salt
Mix the powdered gelatin with the cold water in a large bowl and let sit for 5 minutes.
Heat the cream, 3Tb water, sweetener, vanilla and salt until scalded but not yet boiling. Taste and add more sweetener if not sweet enough.
Pour the heated liquid into the bowl of gelatin and mix well until fully dissolved, then add the remaining 3.5 Tbsp of water.
Pour into serving bowls and chill for 2-4 hours in the fridge.
The final texture will be much wobblier than normal jello desserts, this is so that the dessert "melts" in your mouth. If you find that it is so soft that it will not hold its form at all, then add an extra few grams of gelatin in the next batch.
Vegetarians: If you would like to use agar agar in place of gelatin, check out this site with in-depth details on how to swap them: https://tastingmenu.wordpress.com/2012/04/10/substituting_agar_for_gelatin/
Please note that I used MyFitnessPal to calculate this info, so it may not be 100% accurate, AND I don't think it tracks net carbs, so a portion of the carbs listed may be processed by your body as fiber and not actually absorbed as energy.
net carbs = total carbs - dietary fiber (dietary fiber is what makes up about half of most sugar-alcohols, as well as most of the carbs in coconut flour)