Combine all purpose flour, baking soda, cinnamon and fine sea salt. Whisk until well dispersed.
In a separate bowl add bananas and mash with fork. Bananas should look like applesauce with some chunks when done.
In a large bowl melt the butter. Allow to cool before adding other ingredients.
Add bananas, sugars, sour cream, vanilla and eggs to melted butter. Whisk until smooth and well combined. Batter might look slightly lumpy due to banana pieces.
Add dry ingredients to wet ingredients.
Use spatula to gently fold in dry ingredients to wet. When flour is halfway incorporated, add pecans and continue gently folding.
Preheat oven to 350 F. Prepare 9x5 loaf pan.
Pour batter into loaf pan and smooth out with spatula.
Top with pecans for added crunch. Bake at 350 F for 50 to 60 minutes.
Remove from oven and place on wire rack to cool. Allow to cool in baking loaf for at least 1 hour before removing. Allow to cool completely before slicing.