Method:

Preheat the oven to 180C
Combine the flour, baking powder, salt, sugar, butter and egg yolk in a large bowl. Mix until a breadcrumb consistency then slowly add the water to form a dough. Roll out and press into an oven safe baking dish, up the sides as well.
Prick holes in the crust with a fork, cover with baking paper and beans and blind-bake for 15 minutes.
Heat 500ml of the milk in a large saucepan with the cinnamon stick.
Do not let the milk boil. In a separate bowl, combine the egg yolks, cornflour, flour, sugar and remaining milk into a smooth slurry.
Add a cup of the warm milk into slurry while stirring continuously.
Pour the mixture through a sieve to avoid lumps back into the warm milk mixture.
Stir continuously until the mixture is thick. In a separate mixing bowl, egg whites until soft peaks start to form.
Fold the vanilla and egg whites into the milk tart mixture.
Remove the cinnamon stick and pour the milk tart mixture into the prepared base.
Bake in the oven for 20-25 minutes. Remove from the oven and allow to cool.
Place in the fridge for at least 4-hours to set before dusting with cinnamon and slicing and serving.