1. Preheat the oven to 350 degrees F (175 degrees C). Grease and flour two 9×5 inch loaf pans.
2. SIft the flour, salt, and baking soda into a large bowl. In a separate bowl, mix together the butter or margarine and sugar until smooth. Mix in the bananas, eggs, and walnuts until well blended.
3. Pour the wet ingredients into the dry mixture, and stir until blended. Divide the batter evenly between the two loafs.
4. Bake for 60 to 70 minutes in the preheated oven, until a knife inserted into the crown of the loaf comes out clean. Let the loaves cool in the pans for at least 5 minutes, then turn out onto a cooling rack, and cool completely.
5. Wrap in aluminum foil to keep in the moisture. Ideally, refrigerate the loaves for two hours or more before serving. TIP: Do not taste or cut the loaves in advance.