PREHEAT oven to 350°F Lightly grease 9-inch springform pan.
BEAT butter and sugar in small mixer bowl until creamy. Beat in flour, egg yolk and salt. Press mixture onto bottom and 1 inch up side of prepared pan.
BAKE for 14 to 16 minutes or until crust is set.
MICROWAVE baking bars and cream in medium, uncovered, microwave-safe bowl on MEDIUM-HIGH (70%) power for 1 minute; STIR. The bars may retain some of their original shape. If necessary, microwave at additional 10- to 15-second intervals, stirring just until bars are melted.
BEAT cream cheese, lemon juice, lemon peel and salt in large mixer bowl until smooth. Gradually beat in melted baking bars. Beat in egg whites and whole egg. Pour into crust.
BAKE for 35 to 40 minutes or until edge is lightly browned. Run knife around edge of cheesecake. Cool completely on wire rack. Refrigerate for several hours or overnight. Remove side of springform pan. Garnish as desired.