1. Preheat oven to 300°F. Grease four 7x3 inch loaf pans, and dust lightly with a cinnamon sugar mixture. In a large bowl, cream butter and sugar. Mix in eggs, mashed bananas, sour cream, and vanilla. In separate bowl, mix together salt, baking soda, cinnamon, and flour. Add to wet ingredients. Stir in nuts.
3. Divide into prepared pans.
4. Bake for 1 hour or until toothpick comes out clean.