PREHEAT oven to 375° F. Grease 15 x 10-inch jelly-roll pan.
COMBINE flour, baking soda and salt in small bowl. Beat brown sugar, granulated sugar, butter and peanut butter in large mixer bowl until creamy. Beat in eggs and vanilla extract. Gradually beat in flour mixture.
SPREAD dough evenly into prepared pan. Sprinkle with Baby Ruth; press in lightly.
BAKE for 18 to 20 minutes or until golden brown. Cool completely in pan on wire rack. Cut into bars.