Spray your loaf pan with non stick spray and preheat oven to 325 degrees.
In a bowl add flour, baking soda, cinnamon and salt and mix until combined.
In a different bowl add egg, sugar and oil and mix until combined.
Pour the dry ingredients into the wet ingredient bowl and mix well, scraping the bottom and sides. The mixture will be thick and dry.
Add buttermilk, vanilla and mashed bananas and mix until combined.
Spoon mixture into loaf pan and sprinkle walnuts or pecans over the top.
Bake for 60 minutes or until toothpick inserted into center comes out clean.