1. Preheat oven to 350°F
2. Spray the bottom only of a 13 x 9 inch metal baking pan with nonstick cooking spray.
3. In a large bowl beat cake mix, oil and egg until well blended and crumbly.
4. Stir in nuts.
5. Set aside 1 cup of the crumb mixture.
6. Firmly press remaining crumb mixture on bottom of prepared pan.
7. In a small bowl, combine condensed milk and mashed banana; pour evenly over crust.
8. Top with butterscotch chips and coconut; press down firmly.
9. Sprinkle with reserved crumb mixture.
10. Bake 25-28 minutes or until lightly browned.
11. Cool completely.
12. Cut into bars.