Repeat with other half of dough in other pie plate.
Prick all over with fork and bake for 10 minutes.
No further baking is required.
For filling: Heat milk and melt butter in it. Allow to cool 10 minutes before proceeding with recipe.
Beat eggs with flour, cornstarch, sugar and vanilla. With a ladle, slowly dribble in some of the hot milk mixture while whisking eggs continuously, to temper the eggs and bring them up in temperature. Add all the milk mixture in this way, never forgetting to whisk.
Pour the custard back into the pot and cook, whisking constantly, until custard thickens, about 8 minutes.
Pour into baked shells and sprinkle with cinnamon and sugar.