Clinch Mountain Vinegar Pie
["1 c. sugar", "2 eggs", "2 Tbsp. vinegar", "2 Tbsp. flour or cornstarch", "1 c. water", "small lump butter or margarine", "1/2 tsp. lemon extract"]
["Combine sugar, eggs, vinegar, flour (or cornstarch) and water in double boiler and cook until thick and smooth, stirring occasionally.", "Just before removing from heat, stir in small lump of butter and some lemon extract.", "Pour into baked pie shell.", "If desired, the pie may be topped with frosting or whipped cream."]
["sugar", "eggs", "vinegar", "flour", "water", "lump butter", "lemon extract"]