Make up the Orange Jelly using 1/4 pint of boiling water.
Pour the jelly equally into 12 round silicone moulds, then pop it into the fridge to set.
While you're waiting for the jelly to set whisk the eggs and sweetener in a clean bowl and whisk until you reach the 'ribbon stage'. This is when the mixture has thickened so that when you lift the whisk out it leaves a trail on the surface for a second.
You will probably need an electric whisk for this step.
Fold the sifted flour and vanilla extract into the egg and sweetener mix.
Spray 12 muffin moulds with some low calorie cooking spray and divide the sponge mix equally between them.
Bake at 180°C for 10 minutes, until the sponges are a light golden colour.
When they are cool carefully remove the sponges from the muffin tin - a tablespoon can help with this step! Place the set jelly on top of the sponges.
Carefully melt the chocolate in the microwave - it doesn't take long so keep checking on it! Once melted transfer the chocolate into a disposable piping bag and snip a very small hole in the end.
Drizzle the chocolate evenly over the Jaffa Cakes and allow to set.