Spray a 13x9 pan with cooking spray and preheat the oven to 325 degrees. In a large bowl smash your bananas with a fork. Add cake mix, cranberries, butter, eggs and water. Beat at low speed until combined then at medium speed for 1 minute. Put batter in sprayed pan and top with pecans.
Bake 20-30 minutes or until edges are light golden brown. Cool completely before removing them from the pan. If you would like sprinkle them with powdered sugar.