Preheat oven to 350 and spray a 5 by 9-inch loaf pan with nonstick cooking spray.
In a large bowl, whisk flour, cocoa powder, baking soda, and salt to combine.
In a medium bowl, mash the ripe bananas. Add the melted butter and oil and mix until combined. Mix in the brown sugar, egg, and vanilla and stir until smooth.
Gently fold the wet ingredients into the dry ingredients until almost combined. Stir in 1/2 cup chocolate chips until just combined, be careful not to over mix.
Pour batter into the prepared loaf pan and sprinkle with remaining 1/4 cup chocolate chips. Bake for 50-55 minutes, or until a toothpick inserted into the center of the loaf comes out clean. Cool in pan on wire rack for 10 minutes; use a knife to loosen sides and turn onto wire rack and continue to cool until warm, about 45 minutes. Cut into slices and serve.