Preheat oven to 350 degrees F.
In a mixing bowl, add 1 1/2 cups of flour, baking powder, baking soda, and salt. Whisk together and set aside.
In a separate mixing bowl, add the bananas. Mash until smooth. Add in eggs, honey, sour cream, oil, and vanilla extract. Whisk until fully combined.
Add the dry ingredients into the wet. Stir until just combined. Pour half of the batter into the empty bowl used to mix the dry ingredients. Add 1/4 cup cocoa powder and stir.
In the other bowl with the plain banana bread batter, add 1/4 cup flour. Stir until just combined.
Grease or line a pound loaf pan with parchment paper. Using an ice cream scoop or spoon, alternate adding the plain banana bread batter and chocolate batter to the loaf pan, creating a checkerboard pattern. Using a knife or toothpick, gently swirl the two batters together.
Bake for 43-50 minutes or until the batter has set. Remove from the oven and let cool slightly before enjoying!