Step 1

Preheat the oven to 325°F.  In a large bowl, whisk together the cocoa powder, sugar, and corn starch.  Add in the beaten egg, melted butter, milk, and vanilla.  Stir well to combine.

Step 2

Pour the mixture into the unbaked pie shell being cautious not to over-fill. Bake for 45 to 55 minutes or until a crust has formed completely across the top of the pie and is mostly set. There will still be some jiggle to the pie. Allow to cool completely before slicing and serving. This will allow it to set even more.  Serve with a dollop of whipped cream, if desired.