Stir together sugar, butter, lemon rind and juice in top of double boiler set over hot, not boiling, water until butter melts. Gradually and vigorously stir in eggs; cook, stirring constantly, until mixture is thickened and coats back of spoon, about 15 minutes (temperature should be 160°); do not boil. Strain, if necessary. Pour mixture into bowl; cover surface with plastic wrap and refrigerate until well chilled.

1/3 lemon juice 1 cup sugar 2/3 cup butter 3/4 teaspoon cornstarch 3 eggs Makes 1.25 cups