1cream together butter,sugar,eggs,bananas,vanilla mix them very well then add salt baking soda mix well then add flour.
2pour in to a cooking sprayed 15x10 pan (you can not use a smaller pan it dose not work)bake at 350 25-30 min till cake tester comes out clean. allow to cool completely
3then make frosting
beat; butter,cream cheese,vanilla in a medium bowl till creamy then slowly add powdered sugar till spreadable frosting consistency of your liking.
spread over cooled bars keep leftovers refrigerated!