Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x5 inch loaf pan.

In a large bowl, combine flour, baking soda and salt. In a separate bowl, cream together butter and brown sugar. Stir in eggs and mashed bananas until well blended. Stir banana mixture into flour mixture; stir just to moisten. Add cinnamon and vanilla extract. Pour 1/2 batter into prepared loaf pan, and add walnuts in between before filling the pan with the rest of the batter.

Add a slice of banana at the top for decoration.

Bake in preheated oven for 55 to 60 minutes, until a toothpick inserted into center of the loaf comes out clean. Let bread cool in pan for 10 minutes, then turn out onto a wire rack.