Grease a 9X9 cake pan (cut a piece of parchment and line the bottom of the pan, if you desire)
In a bowl cream the butter and sugar together, using a mixer. Add the bananas and continue to mix until the mixture becomes more liquid. Then, add the remaining ingredients for the cake and mix until incorporated. Set mixture aside
To assmemble the crumb topping
In a bowl put the the soften butter, brown sugar, flour, pecans and cinnamon. Using the back of a fork, push the fork down on top of the ingredients to combine.Continue until the mixture forms into sandy consistency.
Pour ½ of cake batter into the pan. Sprinkle ½ of crumble mixture on top. Add the remaining batter to the pan, and then the remaining crumble.
Bake for 50-60 minutes, until tooth pick from center of cake is clean.