Heat milk and butter in a saucepan. Bring to the boil and remove from the heat.
In a mixing bowl, beat eggs and sugar, cornflour, custard powder, flour and vanilla essence.
Whisk two spoonfuls of the hot milk into the egg mixture to temper the eggs.
Slowly pour the egg mixture into the saucepan and cook until it thickens, stirring continuously.
Cook the mixture for another 2–3 minutes, until thick and smooth. Pour the custard into the baked crusts.
Sprinkle cinnamon over the top and allow to cool before serving.
