1 unbaked pie shell
1/2 cup baking cocoa
1/3 cup cornstarch
1 cup sugar
1/4 tsp salt
3 cups milk
2 tbsp margarine
1 tsp vanilla

Cook cocoa, salt, sugar and cornstarch together while adding milk at medium heat.  Bring this mixture to a boil.  After the mixture slightly cools add vanilla and butter.  Put your mixture into the pie shell and refrigerate for 8 hours.  Whip cream can be added for topping before serving.