Preheat oven to 350º.
Grease the bottom only of a standard size loaf pan with butter or nonstick cooking spray.
Combine flour, baking soda, baking powder and salt in a medium-sized bowl.
Set aside.

Melt butter over medium heat in a small heavy bottomed pot.
Cook until it begins to brown, but not burn; it will smell nutty and fragrant.
Remove from heat, and let cool for 10 minutes.

Peel and dice one banana.
Mash the remaining bananas in a small bowl; set aside.
Heat 1 tablespoon of brown sugar in a small skillet over medium heat until it begins to melt and turn golden.
Add diced banana pieces and saute until well coated and caramelized.
Remove from pan and set aside.

Beat eggs on medium speed in your mixer.
Add brown sugar and beat until foamy and combined.
Add mashed very ripe banana, cooled browned butter, bourbon; beat until mixed well.
Scrape down sides of bowl again with rubber spatula.

On low speed, pour in 1/3 of the flour mixture. Increase mixer speed to medium and mix until just blended.
Pour in 1/3 of buttermilk and beat until just blended.
Repeat this process with remaining flour and buttermilk.
Fold in pecans and caramelized banana pieces.
Pour into prepared loaf pan and bake for 55 to 60 minutes or until a toothpick inserted in center comes out clean.