In small saucepan, mix together sugar, cornstarch and salt,
making sure the cornstarch is evenly distributed.
Gradually stir in water. Place saucepan over moderately high heat
and bring mixture to boil, stirring constantly. Boil ½ min.
Remove pan from heat. Add butter and stir until melted.
Stir in lemon peel and juice. Serve sauce hot.
Sauce may be kept hot, or reheated,
in top of double boiler over simmering water. 1 ½ c. sauce.