Vinegar Pie
["1 Baked 9-inch pie crust", "1 cup water", "1 cup sugar", "1/2 cup butter", "1 egg", "1 tsp. vanilla extract", "2 Tbsp. vinegar", "3 Tbsp. flour"]
["Bring water to a boil and add sugar, butter, egg, vanilla, vinegar and flour.\tCook over low heat until thick.", "Pour into prepared pie crust and let cool.", "Serve with whipped cream."]
["crust", "water", "sugar", "butter", "egg", "vanilla extract", "vinegar", "flour"]