Preheat your oven to 350°F (175°C).
Lightly grease a 9 x 5-inch loaf pan. Place a strip of parchment paper across the center of the pan, leaving a little overhang on each side for easy removal.
Peel the bananas and place them in a large mixing bowl. Mash thoroughly with a fork or potato masher.
Add the granulated sugar, brown sugar, canola oil, and vanilla extract. Stir until well combined.
Add the flour to the bowl. Sprinkle the baking soda, cinnamon, and salt over the flour.
Stir until the ingredients are just combined. Avoid overmixing. The batter will be thick.
Fold in the chopped walnuts.
Transfer the batter to the prepared loaf pan and smooth the top with the back of a spoon.
Sprinkle the brown sugar evenly over the top.
Bake for 50 minutes, or until a toothpick inserted into the center comes out clean.
Remove the pan from the oven and place it on a wire rack. Let the loaf cool for at least 15 minutes before removing it from the pan.
Allow the banana bread to cool completely before slicing.
Slice and serve.