In a bowl whisk the egg yolks until well blended and set aside.
In a medium size pot, combine the cream with milk, salt and vanilla essence and bring to a simmer. Meanwhile, start making the caramel by adding the sugar in a heavy bottomed pan on medium heat.
Let the sugar start to melt and stir occasionally. The sugar will start browning after 5-10 minutes. The darker the caramel, the more taste you will have in your final dessert. Once it reaches an amber dark colour, add the cream mixture carefully while whisking.
Keep whisking until all the bits of caramel are dissolved. Now slowly pour the caramel mixture over the egg yolks while whisking. When the mixture is smooth add it back into the pot and heat up on medium temperature.
Bring the mixture to a temperature between 70 and 80 degrees while whisking constantly. If you don't have a thermometer, test the consistency of the caramel, by running the mixture over a back of a spoon. When the spoon is well coated, the custard is ready. Fill the glasses with the custard and leave to set in the fridge for at least 2-3 hours.