Preheat the oven to 350°F. Butter a 9 x 5 inch loaf pan.
In a medium bowl, whisk together the flour, baking soda, salt. Set aside.
In a separate bowl, whisk the melted butter and sugar. Add the eggs, one at a time, mixing well after each. Stir in the banana until smooth.
Fold in the dry ingredients. Mixing gently until the batter is smooth.
Pour into the prepared loaf pans.
Generously, sprinkle the top of the loaf with walnuts. You might want to gently press them into the batter (not too deep) to make sure they bake in just right.
Bake for about 45 minutes or until a skewer comes out clean.
When you remove from the oven, it is important to let it cool for 20-30 minutes before removing from the pan. Once you do remove it from the pan, let it cool completely and then cut it into slices.