Nannie's Chocolate cream pie

my great grandmother's recipe.

 1 (9inch) graham cracker crust 
4 Tablespoon flour
​ 1 Tablespoon butter
​ 1 Cup sugar
​ 2 Cups milk
 1/4 Teaspoon salt
​ 3 Egg yolks
​ 1/3Cup cocoa
                                                             1 Teaspoon vanilla
​In a medium sauce pot mix dry ingredients. Add milk and cook slowly over medium heat. Beat egg yolks and stir them in, add butter and vanilla. Cook until stiff, then pour into graham cracker pie crust and allow to cool. Top with whipped cream.

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