Pour 250ml of milk into a saucepan. Take about 4-6 tbsp of the milk and put into a small bowl. Bring the milk in a saucepan to a boil while you mix 3 tbsp of corn starch, 3 tbsp of sugar, some vanilla extract and one egg yolk with the rest of the milk. As soon as the milk starts to boil lower the heat and add the starch mixture. Keep stirring until the pudding thickens, keep stirring a little more before you take the pan off the heat and pour the pudding into your mixing bowl.