Real Chocolate Pie
["1 (9-inch) baked pie shell", "2 c. sugar", "4 Tbsp. cocoa (heaping)", "4 Tbsp. all purpose flour (slightly heaping)", "3 egg yolks, beaten", "2 c. milk", "1 stick butter or margarine", "1 tsp. vanilla extract"]
["In a sauce combine sugar, cocoa, and flour.", "Add beaten egg yolks and milk.", "Stir over medium heat until thick.", "Remove from heat.", "Add butter and vanilla.", "Pour into baked pie shell.", "Top with meringue if desired."]
["shell", "sugar", "cocoa", "flour", "egg yolks", "milk", "butter", "vanilla extract"]