If using a pastry pie crust, poke holes into crust with a fork and bake at 350 until it's brown, about 20 minutes. Prepare graham cracker crust according to crumb package directions.
Mix your sugar, flour, salt, cocoa, eggs and milk (all except vanilla and butter) with a whisk.
Cook while stirring on medium until it bubbles and thickens, about five to 10 minutes. If it becomes lumpy, just beat out the lumps. (It will not get any thicker in the oven so cook until it's as thick as you want it.)
Remove from heat and stir in your vanilla and butter. Pour into prepared crust and bake about 10 minutes at 350.
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