Warm the milk and vanilla in a saucepan then set aside.

Mix the egg yolks and sugar together until combined then add the cornstarch and mix it thoroughly.

Slowly pour the warm milk into the egg mixture whilst whisking constantly to avoid any lumps.

Once incorporated, pour the egg and milk mixture back into the saucepan and heat it on a medium-low heat.

Stir the mixture constantly with a wooden spoon until the mixture is very thick in consistency (about 10 minutes). If you find it isn't thickening turn the heat up but keep stirring to avoid scrambling the eggs (use a whisk to get rid of any small lumps if needed).

Once thickened, pour the pastry cream into a clean bowl and place plastic wrap directly on top to stop a skin forming.

Let the mixture cool then place in the fridge until ready to use.