Place all the ingredients into a saucepan and whisk together well to make sure everything is combined.
Cook over a medium – low heat for 15 minutes stirring continuously with a whisk. Do not bring to the boil. It will thicken and you should see a trail when you whisk the mixture.
Take off the heat and leave to cool slightly before pouring into the ramekins on top of the caramel layer.
Put the ramekins in the fridge to set completely for at least 4 hours.