Preheat your oven to 350°F / 175°C. Generously grease a 9x5-inch loaf pan with butter.
In a medium bowl, whisk together the all-purpose flour, whole wheat flour, salt, and baking powder.
Set aside.
In a separate large bowl, use a hand mixer or stand mixer to cream the softened butter and sugar together until light and fluffy.
Beat in the eggs one at a time, followed by the mashed bananas and vanilla extract.
Add the dry to the wet and mix on low speed (or stir by hand) just until combined. Be careful not to overmix; a few lumps in the batter are perfectly fine.
Gently fold in the chopped nuts and shredded coconut with a spatula.
Pour the batter into your prepared loaf pan and spread it evenly.
Bake for 45 to 60 minutes. To check for doneness, insert a toothpick into the center. It should come out with a few moist crumbs attached, but not wet batter. This bread is very moist, so avoid overbaking.
Let the banana bread cool in the pan on a wire rack for 15 minutes before carefully removing it to cool completely.
Do not overmix the batter once you combine the wet and dry . Overmixing develops gluten, which can result in a tough, dense loaf instead of a tender one.
