Preheat your oven to 375 degrees.
In a separate bowl, add dry ingredients( flour, baking soda, cinnamon) and mix together. Set aside.
Cream butter and sugar( white and brown)
Add one egg at a time, beating well in between each addition
Add vanilla, blend well
In a separate bowl, mash bananas( I used a potato masher) and add sour cream to mix.
Mix well.
Add to butter mix and blend well.
Add in dry ingredients, Mix until just incorporated.
Fold in nuts.
Grease your pan...with BUTTER( cooking spray tends to darken the sides too much)
Pour mixture into greased 9x5 loaf pan
Sprinkle Cinnamon sugar mixture over the top. ALL OF IT. You will thank me later.
Bake 50-60 minutes, or until a toothpick comes out clean with only a few crumbs.
Cool completely before you remove the loaf from the pan, but you can cut it after about 20 minutes.
Try not to eat it all at once...
ENJOY!