Preheat the oven to 350 degrees and butter and flour 2 loaf pans. Set aside

In a large bowl, combine the flour, baking soda, salt and walnuts. Whisk for 30 seconds to fully combine. Set aside.

In a large bowl, roughly mash the bananas with a fork, being careful not to turn them into a puree. Add the buttermilk and set aside.

In the bowl of a stand mixer, cream together the butter and sugar until light and fluffy, about 5 minutes. Add the eggs and vanilla and beat until fully incorporated. Stir in the banana mixture just until combined.

Lightly fold the wet ingredients into the dry ingredients until just combined and chunky looking. Scrape batter into prepared pans. Bake until golden brown and toothpick inserted in center comes out with a few crumbs attached, about 55-60 minutes.

Cool on a rack for 5 minutes then remove from pans. Serve warm or at room temperature.