Combine flour baking powder and salt in small bowl set aside Beat together margarine brown sugar and granulated sugar in large bowl until creamy Add pineapple eggs and vanilla beat until blended Stir in flour mixture butterscotch and nuts until blended Pour in 13 x 9-inch baking pan sprayed with vegetable cooking spray Bake at 350 for 40 to 45 minutes or until toothpick inserted in center comes out clean