Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9×5 inch loaf pan, or line with parchment paper leaving an overhang on the long sides for easy removal.
Step 2: In a large bowl, cream together the softened butter, granulated sugar, and brown sugar with an electric mixer on medium speed until light and fluffy, about 2-3 minutes.
Step 3: Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the vanilla extract.
Step 4: Add the mashed ripe bananas to the wet mixture and mix on low speed until just combined. Do not overmix.
Step 5: In a separate medium bowl, whisk together the all-purpose flour, baking soda, ground cinnamon, and salt.
Step 6: Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix; a few streaks of flour are acceptable.
Step 7: Gently fold in the toasted chopped walnuts or pecans with a spatula until evenly distributed.
Step 8: Pour the batter into the prepared loaf pan, spreading it evenly. If desired, sprinkle a few extra chopped nuts on top.
Step 9: Bake for 55-65 minutes, or until a wooden skewer or toothpick inserted into the center of the loaf comes out clean. If the top starts to brown too quickly, tent loosely with aluminum foil.
Step 10: Let the banana nut bread cool in the pan on a wire rack for 10-15 minutes before carefully lifting it out by the parchment paper overhang (if used) or inverting it onto the rack. Allow it to cool completely before slicing and serving.