Prepare the flavored jel desserts in advance. Make according to the box instructions, but reduce the boiling water to ⅔ cup. Make each flavor separately in small plastic boxes or similar, and allow to set fully.
To make the cream layer, pour ½ cup of cold water into a bowl and sprinkle the gelatin over the water. Let it sit for 10 minutes to allow the gelatin to "bloom".
Next, bring some heavy cream and another ½ cup water to the boil in a saucepan. Add the sweetener, and whisk until the sweetener has dissolved.
Remove from the heat and pour it over the gelatin mixture, whisking constantly until the gelatin has fully dissolved.
Let the cream mixture cool to room temperature - it takes about 30 minutes - but make sure you stir it every now and then to prevent a skin forming or it starting to set at the edges.
Meanwhile, use a blunt spatula or similar to score the set jel dessert into random squares, triangles or whatever. It really doesn't matter!
Mix all three flavors of jel dessert together in a large pan or container, mixing them around to evenly distribute them. Pour the cooled cream mixture over the top.
Cover and place in the fridge until set - around 3 hours or overnight.
Score it into 16 squares and serve! Side note: 1g net carb per serving of two blocks!