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

Combine sugar, cornstarch and salt in a large saucepan. Stir in boiling water, lemon peel and lemon juice. Bring to a full boil over moderate heat and reduce heat slightly and boil one minute or until thicken and clear. Stir in butter. Let cool to room temperature before spreading between layers.