Preheat the oven to 350°F. In a large bowl, whisk together the flour, sugar, baking soda and salt. In another bowl, whisk together the eggs, bananas, oil, buttermilk and vanilla until well combined. Add the banana mixture to the flour mixture, stirring just until combined. If desired, fold in the walnuts. Pour the batter into a greased or parchment-lined 9x5-inch loaf pan. Bake the banana bread until a toothpick inserted into the center comes out clean, 1-1/4 to 1-1/2 hours. Cool the bread in the pan at room temperature for 15 minutes. Remove the bread from the pan and place it on a wire rack to cool completely to room temperature before slicing. Editor's Tip: Use a mini offset spatula or butter knife to spread the batter evenly to all four corners of the pan. While baking, if the bread is browning too quickly and the center isn’t fully cooked, cover the top of the pan with aluminum foil.