Chocolate Pie
["1/3 c. cocoa", "1/2 c. plain flour", "1 1/2 c. sugar", "1 1/2 c. milk", "4 egg yolks", "1/4 tsp. salt", "1 tsp. vanilla", "1 Tbsp. butter"]
["Mix dry ingredients. Combine with remaining ingredients. Cook over medium heat, stirring constantly, until thick. Pour in baked pie shell."]
["cocoa", "flour", "sugar", "milk", "egg yolks", "salt", "vanilla", "butter"]