Heat the milk in a medium-sized pot over medium heat.
Meanwhile, in a bowl, combine the sugar, flour, salt, and cocoa.
Add the dry mixture to the milk and cook until thickened, stirring constantly.
Temper the eggs by adding a small amount of the hot milk mixture into the beaten egg yolks and stir. Pour the egg yolk mixture back into the pot, stirring constantly.
Cook the pudding for at least two minutes.
Stir in the vanilla and pour the pudding into the pie shell.
When the chocolate base cools, you can top with Cool Whip or whipped cream.
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Recipe Tips
Blind Baking the Crust and Tempering the Yolks
Two steps in this recipe assume knowledge a first time pie baker may not have.Blind baking the crust. The filling is never baked, so the crust has to be fully baked and cooled before it is filled. Fit the crust into the pie pan, prick the bottom and sides all over with a fork, and line it with parchment weighted down with pie weights or dried beans. Bake at 425°F for about 15 minutes, remove the parchment and weights, and bake another 5 to 8 minutes until the bottom looks dry and lightly golden. Cool it completely on a rack. A warm crust will turn soggy under warm filling.Tempering the yolks. Tempering means raising the temperature of the yolks slowly so they do not scramble. Beat the yolks smooth first, then dribble in a ladle of the hot cocoa mixture while whisking constantly. The yolks should feel warm to the touch before they go back into the pot.