Preheat oven to 350ยบ
Melt Butter and cream together sugars and butter until light and fluffy
Add in smashed bananas, 2 eggs, vanilla extract and sour cream. Whisk to combine
In a separate bowl, mix together flour, baking soda, baking powder, salt, and cinnamon
Pour dry ingredients into wet, stir with a wooden spoon until just combined- Do not over mix
Prepare a 9x9 square pan and pour in batter
Sprinkle the top with crushed nuts and brown sugar
Bake for 30-33 minutes or until toothpick comes out clean
Let cool 10 minutes before slicing
Top with butter and enjoy!