RESERVE 20 raspberries for garnish; refrigerate until ready to use. Mix graham crumbs and butter until well blended; press onto bottom of 9-inch square pan. Refrigerate until ready to use.
BEAT cream cheese, marshmallow creme and lemon juice with mixer until light and fluffy. Stir in remaining raspberries; spread over crust.
REFRIGERATE 4 hours. Top with reserved raspberries just before serving.