Pour the milk into a medium pot, add the cornflour and whisk until smooth.
Add in the rest of the ingredients and place the pot on medium to high heat.
Make sure to stir regularly.
The custard will start to form first on the bottom, when you notice this happening, give it a whisk to make sure the custard stays smooth (continue to whisk now and then).
When it starts to thicken, turn down the heat to low. Still stirring regularly, keep cooking until it’s a thick custard consistency.
Pour into jug and let cool for 15 minutes before refrigerating for at least 3 hours.