1 c. sugar
3 tbsp. cornstarch
1/2 tsp. salt
1 c. water
2 tbsp. grated lemon rind
1/2 c. lemon juice
2 tbsp. butter

In a saucepan stir together the sugar, cornstarch, salt, water, lemon rind, lemon juice and butter and bring to a boil. Reduce the heat and boil for 1 minute, stirring constantly. Let cool, then refrigerate until well chilled and thick. You will have enough filling for an 8 or 9 inch three layer cake.