Place 600ml of milk in a Saucepan as large as a medium sized saucepan and then be patient too gently make the milk hot by gently simmering on the lowest hob heat too prevent the Saucepan from burning on the inside edges

Divide the egg yolks from the egg white's - catch egg yolks between your Fingers and allow the egg white's too flow into a small Dessert Bowl etc. and then place the egg yolks into a large mixing bowl and then add the White Sugar, Vanilla Extract and then the One teaspoon of Cornflour. Mix together with a Wooden Spoon

Add the hot milk too that large mixing bowl and keep stirring with the Wooden Spoon. Add the partially cooked Custard back into the Saucepan and keep stirring with the Wooden Spoon on the lowest hob heat. Use the back of the Wooden Spoon too see if you can draw a line with your Finger - if you can, then your Custard is thick enough. Allow too cool and completely go cold

Mix in 200ml or 300ml of Liquid Double Cream - stir, shake with a Lid on a Plastic Container etc. or blend in a Blitzer and then serve in a 600ml beaker or 500ml mug