Preheat oven to 325 degrees.
Sprinkle some flour in a loaf pan and swirl it around to coat evenly.
In a medium sized bowl add your flour, baking soda, cinnamon and salt. Whisk until combined.
In another small bowl, add the egg, sugar and vegetable oil. Mix until combined.
Add the dry mixture to the egg mixture and stir until well blended.
Add the milk, vanilla, and mashed bananas into your mix. Combine until well incorporated.
Chop the walnuts into small pieces and fold 1/2 cup into your batter.
Pour batter into prepared loaf pan.
Top with remaining walnuts.
Let cool to room temperature, then remove from the loaf pan.