HEAT oven to 350ºF.
LINE 13x9-inch pan with foil, with ends of foil extending over sides; spray with cooking spray. Mix flour, oats and baking soda until blended.
BEAT butter, peanut butter and sugars in large bowl with mixer until light and fluffy. Add egg and vanilla; mix well. Gradually add flour mixture, mixing well after each addition. Stir in chocolate and cranberries; gently press onto bottom of prepared pan.
BAKE 20 to 22 min. or until center is set. Cool completely. Use foil handles to lift dessert from pan before cutting into bars.