Preheat oven to 330 F. Position rack in lower third of oven. Grease and line a 8 1/2 x 4 1/2 inch loaf pan with parchment paper.
In a small bowl, sift together the dry ingredients (flour, baking powder and soda, salt, and cinnamon). Add in the chopped macadamia nuts and stir to coat the nuts. This will keep the nuts from sinking to the bottom of the pan.
In a small microwave safe bowl, melt the butter and coconut oil.
Pour the melted butter and coconut oil into a large bowl and whisk in the eggs, sugar, vanilla and sour cream.
Add in the mashed bananas, stir well.
Add the flour and nuts into the banana mixture, and stir to combine.
Pour the banana bread batter into the prepared loaf pan.
Bake pan 45-60 minutes. Check loaf at 45 minutes for doneness by inserting a toothpick or cake tester into the center of the loaf. If there is still raw batter in the middle, keep baking, checking at 5 minute intervals, until the cake tester comes out clean. If the top is getting too brown, you can tent it with foil.
Let cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.