Great-Grandmother'S Pie
["1/4 c. cocoa or juice and rind of 2 lemons", "1 c. hot water", "butter, size of egg", "1 c. sugar", "1 tsp. vanilla extract", "beaten yolks of 2 eggs", "2 Tbsp. cornstarch"]
["Mix all ingredients well.", "Heat, stirring constantly until thickened.", "Pour into baked pie shell.", "Cover with meringue and brown."]
["cocoa", "water", "butter", "sugar", "vanilla extract", "beaten yolks", "cornstarch"]