Add the sugar-free Jell-O, gelatin and cold water to a small saucepan and stir well. It will look like a thick paste at first.

Cook over low heat, stirring, until all the granules have dissolved and the mixture is liquid - approx 2-3 minutes. Don't let it boil.

Use a jug, squeeze bottle or a tapered spoon to carefully pour the mixture into a silicone candy mold.

Place the filled mold on something firm like a small chopping board (to stop the mold twisting). Let the jello cool, then place in the fridge for 30-40 minutes until set.

Pop the gummies out of the mold. Store in an airtight container in the fridge.