Preheat the oven to 180°C. In a large bowl, whisk the sweetener and eggs until really frothy - this can take around 5 minutes.
Sieve the self-raising flour and cocoa powder into the egg mixture and fold gently until mixed thoroughly.
Spray the silicone moulds with low calorie cooking spray. Fill each of the egg moulds with the cake mix until they are around 3/4 full - this recipe makes 12 cakes. Place in the oven for 17 minutes until cooked through.
Once cooked, pop out of the moulds and leave to cool on a wire rack. Meanwhile, make the icing by stirring around 1.5 teaspoons of water into the icing sugar - it should be thick but runny enough to spread.
Take 1 teaspoon of the icing and put into a separate small bowl with a couple of drops of yellow food colouring and mix well.
Once the cakes are cool, use a teaspoon to create a little dip in each of the cakes.Place a little of the white icing into each dip being careful not to over fill. Drop a tiny bit of the yellow icing into the middle of the white icing to create the "yolk". They're ready to serve!