Ingredients:
2 cups sugar;
5 tablespoons of cocoa;
4 cups milk;
6 egg yolks;
1 stick butter or margarine; 
teaspoon vanilla;
Baked pie shell

Method:
Mix dry ingredients together. Add eggs, butter, and vanilla. Whisk in the milk. Cook over medium heat until thick, stirring often. Pour into baked pie shell. Cover and chill thoroughly.