With the rack in the middle position, preheat the oven to 350˚F (180˚C). Butter a 9 x 5-inch (23 x 13 cm), 6-cup (1.5 litre) loaf pan and line with a strip of parchment paper, letting it hang over two sides.
In a bowl, combine the mashed bananas with the sour cream, maple syrup, oil, egg and vanilla.
In a large bowl, combine both types of flour with the baking soda, cinnamon and salt. Using a wooden spoon or a spatula, add the banana mixture to the bowl and mix just until the dry ingredients are moistened. Add the pecans, if desired. Spread out in the prepared pan.
Bake for 50 minutes or until a toothpick inserted in the centre of the bread comes out clean. Let cool on a wire rack for 1 hour before unmoulding and slicing
Recipes with the "Healthy Pick" stamp have been evaluated by a registered dietitian member of the Ordre professionnel des diététistes du Québec.