Preheat oven to 350 degrees. Lightly grease a (9 x 5) loaf pan with softened butter, and line with a piece of parchment paper for easy removal after baking. (You can also make this into 16 muffins)
Brown the Butter: Melt the butter in a small saucepan over medium heat, swirling and stirring frequently as it slowly turns golden in color as the milk solids brown - about 6 minutes. Set aside to cool.
Mix the Dry ingredients: In a large bowl, whisk together 2 cups plus 2 Tbsp flour, the baking soda and kosher salt.
In another bowl, mash the bananas with a potato masher or a fork, until they are smooth in consistency. Add to that, the brown sugar, vanilla, eggs, yogurt and cooled brown butter. Whisk until everything is combined. Then fold in the dry ingredients, being careful to not overmix. When combined, fold in 1 cup of chopped dark chocolate, and 1 cup chopped pecans (both optional).
Pour the deliciously golden batter into the prepared pan, and bake in the center rack for about 1 hour and 10 minutes. Alternatively, this recipe works great for muffins (makes about 16 muffins) which should take 18-20 minutes to bake.