1 cup white sugar
1/4 cup butter
1 cup milk
1 1/2 cups granulated sugar
1 cup margarine
1 1/2 cups white sugar
2 teaspoons lemon zest
1 teaspoon vanilla extract
1 cup all-purpose flour
1/2 teaspoon salt
Preheat oven to 350 degrees F (175 degrees C).
In a medium saucepan, mix sugar, butter, milk, granulated sugar, margarine, white sugar, lemon zest, and vanilla. Bring to a boil, stirring. Remove from heat and stir in flour and salt. Stir vigorously, but do not boil. Pour over potato mixture. Chill until serving time. Before serving, spoon a thin layer of the mixture over the top of the baked potato.