Preheat oven to 350°F and line a rectangle loaf pan with parchment paper.
In a mixing bowl, combine the flour, baking powder, cinnamon, baking soda and salt, and mix gently until well combined. Set aside.
In another medium mixing bowl, mash your bananas and add in the rest of the wet ingredients. Whisk until smooth. Slowly add your dry ingredients to your wet, being careful not to over mix.
In a small bowl, mix together the swirl ingredients.
Pour about ⅓ of the banana bread base batter into the prepared loaf pan. Swirl ½ of the cinnamon sugar mixture into the top of the batter. Repeat twice, until all of the batter and cinnamon sugar has been used (the top layer will not have a cinnamon sugar swirl).
In another small bowl, combine streusel ingredients and mix together with a fork. Sprinkle over the top of the batter, gently pressing it into the loaf to ensure it sticks after baking.
Bake for about 40-50 minutes, or until a toothpick inserted into the center of the loaf comes out clean.