Preheat your oven to 350°F (180°C). Lightly grease a 9x5-inch loaf pan and line the bottom with parchment paper.

In a medium bowl, whisk together flour, coconut flakes, salt, baking powder, baking soda, and cinnamon.

In a large bowl, beat the butter and sugar with an electric mixer until creamy and light. Add eggs one at a time, mixing well. Then stir in sour cream and vanilla.

Mash the bananas and mix them into the butter mixture.

Gradually add the flour mixture on low speed, mixing just until combined. Fold in the chopped walnuts.

Pour the batter into the prepared pan and sprinkle a few extra walnuts or coconut flakes on top if desired.

Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean. Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.