Fred'S Favorite Raisin Custard Pie
["1 c. seedless raisins", "1 Tbsp. vinegar", "2 1/2 c. water", "3/4 c. sugar", "2 egg yolks", "3 Tbsp. cornstarch", "2 Tbsp. butter"]
["Cook raisins, sugar, 1 1/2 cups water and vinegar about 10 minutes.", "Mix egg yolks, remaining water, cornstarch and butter. Add to raisins and cook until thick.", "Pour into baked pie shell. Serve with whipped topping."]
["raisins", "vinegar", "water", "sugar", "egg yolks", "cornstarch", "butter"]